BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Fe as Local Probe to follow the Competition between Magnetism and Superconductivity in the New Fe-pnictide Superconductors DTSTART;VALUE=DATE-TIME:20100914T120000Z DTEND;VALUE=DATE-TIME:20100914T122000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-130@cern.ch DESCRIPTION:Speakers: Prof. BAGGIO SAITOVITCH\, Elisa (Centro Brasileiro d e Pesquisas Fisicas)\nAbstract\n\nhttp://indico.cern.ch/contributionDispla y.py?contribId=130&sessionId=12&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=130&sessionId=1 2&confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Temperature dependence of the magnetic hyperfine field at 111Cd in ZnO doped with Co. DTSTART;VALUE=DATE-TIME:20100914T101000Z DTEND;VALUE=DATE-TIME:20100914T103000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-137@cern.ch DESCRIPTION:Speakers: Prof. CARBONARI\, Artur (IPEN)\nThe search for room temperature ferromagnetism in wide band gap semiconductor oxides has been quite intensive in the last years. In particular\, ZnO has attracted atten tion since theoretical calculations[1\,2] have indicated that ZnO when dop ed with a transition metal like Co or Mn should present ferromagnetism at room temperature. The results instead of clarifying this issue have howeve r brought more doubts. While many experimental studies confirm the occurre nce of ferromagnetism\, several others do not observe magnetic order in su ch compounds. Hyperfine interactions\, by their nature seem to be very sui ted to investigate these materials and tell something about the existence and origin of the magnetism in such compounds. In the present work powder and bulk samples of ZnO doped with 10 % of Co were prepared by sol-gel m ethod from highly pure metallic Zn(99.9999%) and Co(99.9999%). The samples were characterized by X-ray diffraction (XRD)\, scanning electron microsc opy (SEM)\, energy dispersive X-ray spectroscopy (EDS) and perturbed gamma -gamma angular correlation (PAC) spectroscopy. In order to carry out PAC m easurements carrier-free 111In nuclei were introduced during preparation o f the samples and used as probe nuclei in Zn sites. The XRD patterns showe d that no second phase appeared and SEM images indicated that the samples are highly homogeneous. PAC measurements were carried out in the temperatu re range from 50 K to 295K and the results at 295K before cooling down sho wed that samples of ZnO doped with Co have the same electric quadrupole fr equency reported in literature for pure ZnO. This observation indicates th at Co ions are substituted for Zn ions and have a similar electronic struc ture of Zn ions. Below room temperature one of the samples showed a combin ed magnetic and electric hyperfine interaction from which a magnetic hyper fine field around 1.9 T has been extracted. The temperature dependence of this field showed unusual behavior indicating a first order transition aro und 300 K which suggests a different type of magnetism.\n\nhttp://indico.c ern.ch/contributionDisplay.py?contribId=137&sessionId=12&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=137&sessionId=1 2&confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Angular correlation studies on 172Lu(172Yb) in GaN and measurement at low temperature DTSTART;VALUE=DATE-TIME:20100913T122000Z DTEND;VALUE=DATE-TIME:20100913T124000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-25@cern.ch DESCRIPTION:Speakers: Mr. VALENTINI\, Riccardo (HISKP der Universität Bon n)\nFor optoelectronic devices semiconductors with large band gap doped wi th rare earth are used. Doping is generally performed during growth but fo r more structured doping the ion implantation technique is preferable. The perturbed angular correlation technique is an ideal tool to study the ann ealing behavior of semiconductors after implantation. Usually\, this metho d is only able to measure the absolute value but not the sign of the elect rical field gradient (EFG) acting onto the quadrupole moment of the implan ted probe. An adequate rare earth isotope for such investigations of semic onductors is 172Yb.\nThe temperature dependence of the hyperfine fields fo r 172Lu(172Yb) in GaN has been analyzed. The total EFG at the site of this probe is a superposition of the lattice EFG due to the GaN wurtzite struc ture and the EFG due to the 4f-shell of the rare earth probe itself. The l atter is strongly temperature dependent and opposed to the lattice EFG whi ch in contrast is nearly constant since the lattice parameters change only negligibly with temperature.\nAt elevated temperatures all crystal field split levels of the 4f-shell are equally populated. But at low temperature s the lowest level is occupied preferentially. Sign and magnitude of the E FG produced by the 4f shell can be calculated. Depending on which of the l evels is lowest in energy it was possible to determine the sign of the lat tice field gradient.\n\nhttp://indico.cern.ch/contributionDisplay.py?contr ibId=25&sessionId=7&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=25&sessionId=7& confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Recent developments in Collinear Laser Spectroscopy at ISOLDE\, CE RN. DTSTART;VALUE=DATE-TIME:20100913T071500Z DTEND;VALUE=DATE-TIME:20100913T075500Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-27@cern.ch DESCRIPTION:Speakers: Prof. NOERTERSHAEUSER\, Wilfried (Universität Mainz )\nOptical spectroscopy is known to provide very accurate and model-indepe ndent data on spins\, electromagnetic moments and charge radii of nuclear ground states. Collinear laser spectroscopy is long known to be a general technique\, applicable to a large variety of elements\, but was also devel oped continuously towards higher sensitivity and/or accuracy to scope with even more exotic species. At COLLAPS\, the collinear laser spectroscopy s etup at ISOLDE\, we have applied a frequency-comb based technique to measu re the charge radii of the beryllium isotopes including the one-neutron ha lo nucleus Be-11. Here\, high accuracy was required and uncertainties in h igh voltage calibrations had to be eliminated by simultaneous spectroscopy in collinear and anti-collinear geometry. ISCOOL\, a radio-frequency cool er and buncher came recently into operation and was for the first time app lied at ISOLDE for the spectroscopy of copper and gallium isotopes and inc reased sensitivity by orders of magnitude. The isotope chains of both isot opes offered surprises concerning the spin values of the neutron-rich isot opes. Moreover\, a new technique combining optical pumping and ß-asymmetr y detection was applied for isotope shift shift measurements of Mg isotope s. In this way we were able to cover the chain of Mg isotopes across the c omplete sd shell to study the nuclear shape development during the transit ion into the island of inversion. In my talk I will present these methodol ogical developments and the outstanding results that were obtained with th ese techniques at the COLLAPS experiment.\n\nhttp://indico.cern.ch/contrib utionDisplay.py?contribId=27&sessionId=2&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=27&sessionId=2& confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Proton Dynamics in One-dimensional Hydrogen-bonding System in Mole cular Co-crystals TMP-D2ca and DMP-H2ca DTSTART;VALUE=DATE-TIME:20100916T120000Z DTEND;VALUE=DATE-TIME:20100916T122000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-20@cern.ch DESCRIPTION:Speakers: Prof. ASAJI\, Tetsuo (Nihon University)\nRecently\, hydrogen-bonded supramolecular co-crystals have attracted much interest in aim for functional materials such as ferroelectrics [1]. By use of 35Cl n uclear quadrupole resonance (NQR) we have studied an organic ferroelectric \, phenazine(Phz)-chloranilic acid (H2ca) co-crystal\, Phz-H2ca\, and foun d an electric field gradient fluctuation probably due to a proton dynamics in hydrogen bond [2]. For the detection of rather slow motion of proton in the hydrogen-bonding system\, NQR spin-lattice relaxation of the nearby atom will be quite sensitive. In the co-crystal of tetramethylpyrazine (T MP) with H2ca\, TMP-H2ca\, the spin-lattice relaxation time (T1) of 35Cl N QR showed a steep decrease with increasing temperature above ca. 250 K. Th e decrease could be explained by the Arrhenius law with the activation ene rgy of 35 kJ mol-1 [3]. In the present paper we studied a possible proton motion in another compound with a similar one-dimensional hydrogen bond\, DMP-H2ca\, the co-crystal between 2\,6-dimethylpyrazine (DMP) and H2ca. Th e isotope effect on the hydrogen motion by deuteration of the acid hydroge n in TMP-H2ca was also studied. Fig. 1 shows temperature dependence of 35C l T1 of TMP-D2ca compared with that of TMP-H2ca. By the deuteration the ac tivation energy increased to 50 kJ mol-1. The deuteron motion was confirme d by 2H NMR spin-lattice relaxation measurements which resulted in the act ivation energy of 49 kJ mol-1. Fig. 2 shows temperature dependence of 35Cl T1 of DMP-H2ca. In this compound the relaxation is dominated by lattice v ibration suggesting no transfer motion of proton between the acid and base molecules. \n\n\nReferences\n[1] S. Horiuchi and Y. Tokura\, Nature Mater ials 7\, 357-366 (2008).\n[2] T. Asaji\, J. Seliger\, V. Žagar\, M. Sekig uchi\, J. Watanabe\, K. Gotoh\, H. Ishida\, S. Vrtnik\, and J. Dolinšek\, J. Phys.: Condens. Matter 19\, 226203 (2007).\n[3] T. Asaji\, Y. Yoshimur a\, and D. Amino\, Hyperfine Interact. 179\, 1-7 (2007).\n\nhttp://indico. cern.ch/contributionDisplay.py?contribId=20&sessionId=16&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=20&sessionId=16 &confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:NMR-ON study of 197PtNi DTSTART;VALUE=DATE-TIME:20100913T083500Z DTEND;VALUE=DATE-TIME:20100913T085500Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-124@cern.ch DESCRIPTION:Speakers: Dr. OHTSUBO\, Takashi (Niigata University)\nHyperfin e Interactions\n\nhttp://indico.cern.ch/contributionDisplay.py?contribId=1 24&sessionId=4&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=124&sessionId=4 &confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Ab Initio Hyperfine Interactions as a Powerful Tool to Identify th e Metal Binding Site in Biological Systems: Cd2+ in DNA Bases. DTSTART;VALUE=DATE-TIME:20100916T082000Z DTEND;VALUE=DATE-TIME:20100916T084000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-128@cern.ch DESCRIPTION:Speakers: Mr. DIVNA PETERSEN\, Philippe Alexandre (Universidad e de São Paulo)\nHyperfine interactions can be a powerful tool to identif y local environments in many different systems. Recently it has been drawn attention to the possible application of the Time Differential Perturbed Angular Correlation (TDPAC) technique to study differences in the Nuclear Quadrupole Coupling constants ( υQ ) at Cd probes in mouse DNA infected w ith the Trypanosoma Cruzi. The electric contribution to the hyperfine inte raction is usually expressed as the nuclear quadrupole coupling frequency υQ which is given by the product of the nuclear quadrupole moment Q and t he Electric Field Gradient (EFG) at the nucleus. The EFG can be theoretica lly obtained from an ab initio electronic structure calculation. The 111In → 111Cd β decay can be used in a TDPAC measurement to investigate the Cd metal binding to DNA. The interaction of the metal with the DNA bases c an change many aspects of the base pairing [1]. Here we study electric hyp erfine properties of Cd bound to some DNA bases. The methodology used for the electronic structure calculations is based on the Kohn Sham [2] scheme of the Density Functional Theory (DFT) and the Car-Parrinello [3] method. We use the Projector Augmented Wave [4] method as embodied in the (CP-PAW ) computational code. The results of EFG and energies are discussed as fun ction of water molecules present in the Cd²+ environment and compared wit h TDPAC measurements at Cd probes in mouse DNA infected with the Trypanoso ma Cruzi.References [1] J. V. Burda\, J. Sponer\, J. Leszczynski\, P. Hobz a\, J. Phys. Chem. B.\, 101\, 9670 (1997). [2] W. Kohn\, L. J. Sham\, Phys . Rev. B.\, 140\, 1133 (1965).[3] P. E. Blöchl\, Phys. Rev. B.\, 50\, 179 53 (1994).[4] R. Car e M. Parrinello\, Phys. Rev. Lett. 55\, 2493 (1985).\ n\nhttp://indico.cern.ch/contributionDisplay.py?contribId=128&sessionId=16 &confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=128&sessionId=1 6&confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:PAC study of the dynamic hyperfine interactions at 111In-doped Sc2 O3 semiconductor and comparison with ab initio calculations DTSTART;VALUE=DATE-TIME:20100913T124000Z DTEND;VALUE=DATE-TIME:20100913T130000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-59@cern.ch DESCRIPTION:Speakers: Mr. MUÑOZ\, Emiliano Luis (Departamento de Física e Instituto de Física La Plata (IFLP\, CONICET-UNLP)\, Facultad de Cienci as Exactas\, Universidad Nacional de La Plata\, CC 67\, 1900 La Plata)\, M r. RICHARD\, Diego (Departamento de Física e Instituto de Física La Plat a (IFLP\, CONICET-UNLP)\, Facultad de Ciencias Exactas\, Universidad Nacio nal de La Plata\, CC 67\, 1900 La Plata\, Argentina.)\nThe combined experi mental and theoretical approach based on electric-field gradient (EFG) det erminations by means of hyperfine interaction measurements and ab initio p redictions at impurity atoms has been shown to be a powerful tool to unrav el structural and electronic characterizations of impurities in solids\, i n particular in semiconductor oxides [1-3]. In this work\, PAC experiments using 111In-difussed Sc2O3 polycrystals have been performed at the IPEN f acility in order to measure the Electric-Field Gradient (EFG) at (111In (E C)-->) 111Cd nuclei located at the cation site of the semiconductor lattic e. The experimental results are compared with ab initio calculations perfo rmed with the Full-Potential Augmented Plane Wave plus local orbital (FP-A PW+lo) method in the framework of the Density Functional Theory (DFT). The PAC experiments were carried out in the temperature range 10 K – 900 K. The PAC spectra obtained in these measurements shows two very well-define d quadrupole frequencies along the whole temperature range\, pointing to t he fact that 100% of the probes are located at both nonequivalent cation s ites of the bixbyite structure. Nevertheless\, the spectra are dampened at certain intermediate temperatures\, indicating the presence of dynamic hy perfine interactions that were analyzed with a perturbation factor based o n the Bäverstam and Othaz model [4\,5]. The FPAPW+lo calculations were pe rformed using the Wien2K code. From the ab initio-experimental comparison\ , we can conclude that the Cd impurities localized at the axially symmetri c D sites of the crystal structure do not present dynamic interactions whi le that the Cd probes localized at the asymmetric C sites present apprecia ble dynamic interactions attributed to the so-called after-effects that fo llow the electron-capture decay of the 111In parent isotope of the 111Cd i mpurity tracer. This scenario could be supported in terms of the EFG beha viour\, predicted by the ab initio calculations\, at Cd impurities as a fu nction of the charge state of the impurity located at the different cation sites of the structure.\n\nhttp://indico.cern.ch/contributionDisplay.py?c ontribId=59&sessionId=7&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=59&sessionId=7& confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Donor-Acceptor Complexes in ZnO DTSTART;VALUE=DATE-TIME:20100913T120000Z DTEND;VALUE=DATE-TIME:20100913T122000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-51@cern.ch DESCRIPTION:Speakers: Dr. DEICHER\, Manfred (Technische Physik\, Universit ät des Saarlandes\, D-66041 Saarbrücken\, Germany)\nOne of the main obst acles to the technical application of many wide-gap semiconductors represe nts the difficulty to achieve reliable and sufficient p-type or n-type dop ing. Possible causes are the electrical compensation of dopants by native defects or other impurities present in the material. For the II-VI semicon ductors CdTe\, ZnTe\, and ZnSe it has been shown [1\,2] by perturbed Gamma -Gamma angular correlation spectroscopy (PAC) that the concurrent presence of In donors and group-V acceptors leads to the formation of neighboring donor-acceptor pairs. In case of ZnO\, the affinity to form donor-acceptor complexes may help to overcome the limitations of p-type doping of this m aterial as outlined in the theoretically proposed concepts of cluster-dopi ng [3] or co-doping [4].\nHere\, we report on PAC results obtained by co-d oping experiments of ZnO using the donor 111In and different group-V accep tors. Fig. 1 shows a PAC spectrum obtained after the implantation of ZnO w ith 111In and P and after annealing at 850 K. Besides the lattice electric field gradient (EFG) due to the wurtzite structure of ZnO (nQ Lattice = 3 1 MHz)\, two additional EFG caused by the formation of In-defect complexes are observed. They are characterized by two slightly different nearly axi ally symmetric EFG with nQ1 = 175(1) MHz (Eta = 0.1) and nQ2 = 155(2) MHz (Eta = 0). Due to the wurtzite structure of ZnO having different nearest n eighbor distances along the c axis and in the basal plane\, respectively\, even for identical defect complexes two different EFG are expected to occ ur. The magnitudes of the EFG observed here are similar to that of the EFG known for In-acceptor complexes in other II-VI semiconductors [1\,2]. The nature of the defects in ZnO and the efficiency of different co-doping pr ocedures will be discussed.\nThe results of first PAC experiments on the f ormation of donor-acceptor complexes using group-VII donors in ZnO utilizi ng the radioactive donor 77Br will be discussed\, as well.\n\nThis work ha s been supported by the Bundesministerium für Bildung und Forschung (BMBF ) under contract no. 05KK7TS1.\n\n[1] V. Ostheimer\, A. Jost\, T. Filz\, S t. Lauer\, H. Wolf\, and Th. Wichert\, Appl. Phys. Lett. 69\, 2840 (1996). \n[2] S. Lany\, P. Blaha\, J. Hamann\, V. Ostheimer\, H. Wolf\, and Th. Wi chert\, Phys. Rev B 62 R2259 (2000).\n[3] L.G. Wang and A. Zunger\, Phys. Rev. Lett. 90\, 256401 (2003).\n[4] T. Yamamoto and H. Katayama-Yoshida\, Physica B 302-303\, 155 (2001).\n\nhttp://indico.cern.ch/contributionDispl ay.py?contribId=51&sessionId=7&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=51&sessionId=7& confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Low Temperature Nuclear Orientation Studies of the Magnetic Struct ures of RNiAl4 in Applied Magnetic Fields DTSTART;VALUE=DATE-TIME:20100916T124000Z DTEND;VALUE=DATE-TIME:20100916T130000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-90@cern.ch DESCRIPTION:Speakers: HUTCHISON\, Wayne (University of NSW at ADFA)\nThe f amily of metamagnetic compounds RNiAl4 (R = rare earth) exhibits a range o f interesting magnetic behaviours. There are multiple magnetic phases\, a nd crystal field driven differences in anisotropy and behaviour when diffe rent rare earth ions (R) are present in the compound. TbNiAl4 is one illu strative example. It has two phase transitions (three phases) as a functio n of temperature in low applied magnetic field\, and also at least three p hases as a function of applied magnetic field at low temperature [1]. Ali gned with the first of these field driven transitions is a large inverse m agneto-caloric effect (MCE) [2]. Recent neutron diffraction studies carri ed out on single crystal TbNiAl4\, in applied magnetic fields\, show the o nset of an incommensurate antiferromagnetic ordered phase above the first field induced phase transition [3]. This observation vindicates the existe nce of the higher entropy state at higher applied field that is required f or an inverse MCE but contradicts the predictions of other authors who sug gest a spin flop transition [4]. Low Temperature Nuclear Orientation (LTNO ) can also be usefully applied to TbNiAl4 and other RNiAl4 compounds to in vestigate magnetic structure. In the case of the Tb compound\, neutron ac tivation is used to create in situ 160Tb LTNO probes. However\, as we foun d recently\, TbNiAl4 crystals must be annealed after thermal neutron irrad iation in order to remove damage and restore full gamma-ray anisotropy [5] . In this paper\, we present new LTNO results for annealed TbNiAl4\, in a pplied fields extending to 9 tesla. These results support the model of mag netic struture revealed by the earlier neutron diffraction studies. LTNO i s also applied to crystals of compounds with R = Nd and Pr. These additio nal studies magnetic fields sufficient to traverse the respective first me tamagnetic transitions were also used and behaviours similar to the TbNiAl 4 case were observed.\n\nhttp://indico.cern.ch/contributionDisplay.py?cont ribId=90&sessionId=12&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=90&sessionId=12 &confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:LHC DTSTART;VALUE=DATE-TIME:20100913T092500Z DTEND;VALUE=DATE-TIME:20100913T100500Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-179@cern.ch DESCRIPTION:Speakers: MANGANO\, Michelangelo (CERN)\nhttp://indico.cern.ch /contributionDisplay.py?contribId=179&sessionId=22&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=179&sessionId=2 2&confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:14N NQR study of proton position and dynamics in some hydrogen bon ded organic ferroelectrics DTSTART;VALUE=DATE-TIME:20100916T095000Z DTEND;VALUE=DATE-TIME:20100916T101000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-67@cern.ch DESCRIPTION:Speakers: Prof. SELIGER\, Janez (University of Ljubljana)\nnuc lear quadrupole resonance\n\nhttp://indico.cern.ch/contributionDisplay.py? contribId=67&sessionId=28&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=67&sessionId=28 &confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Modeling Complex Diffusion Mechanisms in L12-Structured Compounds DTSTART;VALUE=DATE-TIME:20100917T095000Z DTEND;VALUE=DATE-TIME:20100917T101000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-114@cern.ch DESCRIPTION:Speakers: ZACATE\, Matthew (Northern Kentucky University)\nSem iconductors\, Metals and Insulators\n\nhttp://indico.cern.ch/contributionD isplay.py?contribId=114&sessionId=7&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=114&sessionId=7 &confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Quadrupolar Perturbed NMR in Inorganic Nanomaterials DTSTART;VALUE=DATE-TIME:20100915T082000Z DTEND;VALUE=DATE-TIME:20100915T084000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-3@cern.ch DESCRIPTION:Speakers: Prof. PANICH\, Alexander (Ben-Gurion University of t he Negev)\nInorganic nanostructures reveal a number of applications in ele ctronics\, magnetic recording\, as low-friction and nano-bio materials. Ho wever\, our knowledge about properties of inorganic nanomaterials is still limited. Quadrupolar perturbed NMR is an excellent tool in studying the l ocal site symmetry\, chemical bonding and electronic structure of inorgani c nano-particles comprising quadrupole nuclei. I will review my own and li terature data on NMR spectra and relaxation measurements of quadrupole nuc lei in several inorganic nano-compounds such as boron nitride nanotubes\, vanadium oxide nanotubes and molybdenum sulfide fullerenes. Detailed analy sis of the spectra and their comparison with those in bulk samples will be done. The obtained findings allow us making conclusions about the local c rystal structure\, electronic structure and bonding in the inorganic nanos ized compounds.\n\nhttp://indico.cern.ch/contributionDisplay.py?contribId= 3&sessionId=13&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=3&sessionId=13& confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Entanglement in nuclear quadrupole resonance DTSTART;VALUE=DATE-TIME:20100916T101000Z DTEND;VALUE=DATE-TIME:20100916T103000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-7@cern.ch DESCRIPTION:Speakers: Prof. FURMAN\, Gregory (Ben Gurion University)\nQuan tum systems in an entangled state [1] can be used as a primary quantum inf ormation channel to perform computational [2]\, communicational [3]\, metr ological [4\, 5] and cryptographic tasks that are impossible for classical systems. These possible applications of entangled quantum states stimulat e intensive research in the fields of generation and manipulation of them. Entangled states may appear in various systems of interacting quantum par ticles\, such as phonons\, ions\, electron\, nuclear spins\, and of a sing le particle interacting with environment.\n We study entanglement be tween quantum states of multi level spin system of a single particle consi dering a nucleus with spin 3/2 in both the internal electric field gradien t and the external magnetic field. It was shown that entanglement is achie ved by applying a magnetic field to a single particle at low temperature ( 5 mK). In this temperature range\, the numerical calculation revealed the coincidence between magnetization and concurrence. As a result\, the magn etization can be used as an entanglement witness for such systems. \n1. C. H.Bennett \, G.Brassard \, C.Crepeau \, R.Jozsa \, A.Peres \, and W. K.Wo otters \, Phys. Rev. Lett. 70\, 1895 (1993).\n2. C.H. Bennett and G.Brassa rd \, Proceedings of IEEE International Conference on Computers\, Systems and Signal Processing\, Bangalore\, India\, pp. 175-179\, December 1984.\n 3. P.Shor\, in Proceedings of 35th Annual Symposium on the Foundations of Computer Science (IEEE Computer Society\, Los Alamitos\, CA\, 1994)\, p. 1 24-134.\n4 P. Cappellaro \, J. Emerson \, N. Boulant \, C. Ramanathan \, S . Lloyd \, and D. G. Cory \, Phys. Rev. Lett.\, 94\, 020502 (2005).\n5 C.F .Roos\, K.Kim\, M.Riebe\, R. Blatt\, Nature 443\, 316 (2006).\n\nhttp://in dico.cern.ch/contributionDisplay.py?contribId=7&sessionId=11&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=7&sessionId=11& confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Quadrupole interaction in the solid halogens - a new (not final) l ook DTSTART;VALUE=DATE-TIME:20100917T080000Z DTEND;VALUE=DATE-TIME:20100917T082000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-108@cern.ch DESCRIPTION:Speakers: HAAS\, Heinz (Instituto Tecnologico et Nuclear ITN)\ nThe nuclear quadrupole interaction in the molecular crystals of chlorine\ , bromine and iodine has been studied very early after the introduction of the NQR method. One should thus believe that precise experimental results are available. It will be argued here that for Cl2 and Br2 this is not th e case at all. Obviously several attempts on interpreting the existing dat a have been made. Actually already in the first theoretical analysis [1] d oubts on the results for solid Br have been raised\, but afterwards ignore d. In a pioneering work really free from parameters the EFG for solid Cl2\ , Br2 and I2 was calculated with the density functional method FLAPW [2]. The comparison of the calculated asymmetry parameters  with experiment was inconclusive\, however. The intermolecular interaction that creates  also will have an influence on the interaction frequency when compared to the free molecule value0. Since precise experimental data for th is shift /0 are available\, here an attempt is described to treat both effects on the same footing. The same method previously used to dete rmine the halogen nuclear quadrupole moments [3] was therefore applied to the free halogen molecules and the solids. It is obvious that the FLAPW ca lculations overestimate the frequency shift by a factor of about 2 in all three cases. It is thus extremely likely that the same holds also for . Under the assumption that the degree of overestimation for /0 an d  is the same\, “corrected” values for  may be obtained. This r esults in a perfect agreement with the precisely known value for I2. It co uld be demonstrated with FLAPW calculations of expanded unit cells that th e effects of the intermolecular interaction on /0 and  are cor related. From these calculations also for the first time a realistic theor etical result for the sublimation enthalpies is obtained. It may be hoped that the interpretation presented here will act as a stimulus for new expe riments and theoretical treatments that can describe the intermolecular in teraction better than FLAPW. The results are summarized in Table 1:\n\nhtt p://indico.cern.ch/contributionDisplay.py?contribId=108&sessionId=19&confI d=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=108&sessionId=1 9&confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Temperature dependence of the hyperfine fields of 111In in sapphir e (Al2O3) single crystals DTSTART;VALUE=DATE-TIME:20100913T130000Z DTEND;VALUE=DATE-TIME:20100913T132000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-32@cern.ch DESCRIPTION:Speakers: Mr. STEFFENS\, Michael (HISKP der Universität Bonn) \nThe decay of 111In to 111Cd via electron capture\, accompanied by Auger electrons\, leaves the outmost atomic shell of the Cadmium in a highly ion ized state. \nIn PAC measurements\, this so called “electron capture aft er effect” leads to a significant loss of anisotropy and can be associat ed with a highly fluctuating electric field gradient (EFG).\nThe recovery of the 111Cd shell by electronic recombination depends on the concentratio n and the mobility of charge carriers in the material. For insulators\, th e recombination timescale lies in the nanosecond regime\, the generic time scale of hyperfine interaction processes as investigated by the PAC method . \nIn previous measurements the fraction of undisturbed probe atoms showe d a strong and reversible dependence on the sample temperature [1].\nOur c urrent approach is to determine and alter the conditions under which elect rons are sufficiently available to suppress the “after effect”.\nSapph ire single crystals were ion implanted with 111In at the mass separator in Bonn. After rapid thermal annealing the samples were held at temperatures up to 1000 K. To alter the recombination characteristics and to study the influence of acceptor and donator levels\, the samples were additionally doped with several concentrations of Si\, Cr and P.\n\nhttp://indico.cern. ch/contributionDisplay.py?contribId=32&sessionId=7&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=32&sessionId=7& confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Electron penetration into the nucleus and its effect on the quadr upole interaction DTSTART;VALUE=DATE-TIME:20100917T074000Z DTEND;VALUE=DATE-TIME:20100917T080000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-30@cern.ch DESCRIPTION:Speakers: Ms. KOCH\, Katrin (Instituut voor Kern- en Stralings fysica\, KULeuven\, Max Planck Institute for Chemical Physics of Solids\, Dresden\, Germany)\, Mr. COTTENIER\, Stefaan (Center for Molecular Modelin g -- Universiteit Gent)\nA series expansion of the interaction between a n ucleus and its surrounding electron distribution provides terms that are w ell-known in the study of hyperfine interactions: the familiar quadrupole interaction and the less familiar hexadecapole interaction. If the penetra tion of electrons into the nucleus is taken into account\, various correct ions to these multipole interactions appear. The best known correction is a scalar term related to the isotope shift and the isomer shift. This cont ribution discusses a related tensor correction\, which modifies the quadru pole interaction if electrons penetrate the nucleus: the quadrupole shift. We describe the mathematical formalism and provide first-principles calcu lations of the quadrupole shift for a large set of solids. Fully relativis tic calculations that explicitly take a finite nucleus into account turn o ut to be mandatory. Our analysis shows that the quadrupole shift becomes a ppreciably large for heavy elements. Implications for experimental high-pr ecision studies of quadrupole interactions and quadrupole moment ratios ar e discussed. This contribution brings alive the results that are report ed in Ref. [1]\, updated with very recent experimental follow-up work [2]. References [1] K. Koch\, K. Koepernik\, D. Van Neck\, H. Rosner\, S. Cot tenier\, Physical Review A 81 (2010) 032507\, [2] D. Dewald\, J. Grabow\, in preparation\n\nhttp://indico.cern.ch/contributionDisplay.py?contribId=3 0&sessionId=19&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=30&sessionId=19 &confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Defect induced magnetic interaction in highly oriented pyrolytic g raphite (HOPG): A local investigation using TDPAD method DTSTART;VALUE=DATE-TIME:20100914T132000Z DTEND;VALUE=DATE-TIME:20100914T134000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-36@cern.ch DESCRIPTION:Speakers: Prof. MISHRA\, S.N. (Tata Institute of Fundamental R esearch\, Homi Bhabha Road\, Mumbai-400005\, India)\nDefect induced magnet ic interaction in highly oriented pyrolytic graphite (HOPG): A local inves tigation using TDPAD method.\nS.N. Mishra\,1 S.K. Mohanta\,1\,2 S.K. Sriv astava2 \n1Dept. of Nuclear and Atomic Physics\, Tata Institute of Fundame ntal Research\, Mumbai-400005\, India\, \ne-mail: mishra@tifr.res.in\n2Dep t. of Physics and Meteorology\, Indian Institute of Technology\, Kharagp ur-721302\, India\nDefect induced magnetism in carbon based systems have l ong been the subject under extensive investigation\, not only for the natu re of magnetism in s\, p electron systems but also for its potential to pr actical applications. The discovery of ferromagnetism at room temperature in pure carbon materials has given a new impetus for magnetic studies in g raphite and other carbon materials [1\,2]. It has been suggested that defe cts play a key role for the ferromagnetic ordering observed in graphite. \ nHere\, we present magnetic hyperfine field of 19F measured by time differ ential perturbed angular distribution technique. The 19F probes were produ ced via the heavy-ion reaction 12C(12C\,αp)19F using pulsed 12C beam at a n energy of 40 MeV. The energetic 12C beam impinging on a 1 mm thick HOPG sample\, used as the stopper\, also creates high concentration of defects. The approach adopted here\, thus serves the dual purpose of creating defe cts and studying the magnetic interactions arising thereof. For the detect ion of hyperfine fields we have used the 5/2 isomeric state in 19F with half-life T1/2=88.5 ns\, g-factor gN = 1.44 and\, quadrupole moment Q = - 0.12 b which offers high sensitivity towards magnetic interactions. Typica l spin rotation spectra R(t) measured for 19F in HOPG are shown in Fig 1. The R(t) spectra show superposition of two frequencies having L = 64 an d 93 MHz and intensity ratio of 45:55 at 15 K. Fig 2 shows the temperature dependence of the magnetic hyperfine field Bhf derived from the expressio n Bhf = (L/gNNBext)-Bext. The L for the two components show di stinctly different temperature dependence yielding Bhf ~5 kG and 0.8 kG at T = 0. The observed results indicate the presence of strong magnetic inte raction in HOPG. Supported by ab-initio calculations performed for a numbe r of defect configurations around a F impurity in graphite\, we assign the high field component to substitutional site with single vacancy/interstit ial C\, and the low field component to F at substitutional/interstitial si tes without any vacancy in its neighborhood. \n \n Fig 1. Spin rota tion spectra at 15 and 35K . Fig 2. Hyperfine field as a function o f temperature.\n\n\nReferences\n[1] T. Makarova et al.\, Carbon based magn etism\, Amsterdam: Elsevier\; p. 371-96 (2006).\n[2] P. Esquinazi et al.\, Phys. Rev. B 66\, 024429 (2002).\n\nhttp://indico.cern.ch/contributionDis play.py?contribId=36&sessionId=12&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=36&sessionId=12 &confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Study of Dependence of Quasi-Particle Alignment on Proton and Neut ron Numbers in A= 80 Region through g-factor Measurements* DTSTART;VALUE=DATE-TIME:20100913T100500Z DTEND;VALUE=DATE-TIME:20100913T102500Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-35@cern.ch DESCRIPTION:Speakers: Prof. ZHU\, Shengyun (China Institute of Atomic Ener gy)\, Prof. YUAN\, Daqing (China Institute of Atomic Energy)\nStudy of Dep endence of Quasi-Particle Alignment on Proton and Neutron Numbers in A= 80 Region through g-factor Measurements*\n\nYuan Daqing\, Fan Ping\, Zheng Y ongnan\, Zuo Yi\, Zhou Dongmei\, Zhang Qiaoli\, Wu xiaoguang\, \nLi Guangs heng\, Zhu Lihua\, Xu Guoji\, Fan Qiwen\, Zhang Xizhen and Zhu Shengyun**\ n\nChina Institute of Atomic Energy\, P.O. Box 275-50\, Beijing 102413\nEm ail: zhusy@ciae.ac.cn\n\nThe interplay between the collective rotation and the quasi-particle alignment is a significant feature of nuclear structur e at high spins. The g-factors of intra-band high spin states of the groun d rotational band can provide direct and unique information on quasi-parti cle alignment since the g-factors of the high-j proton and the high-j neut ron are positively large and negatively small\, respectively. \nThe g-fact ors of high spin states of the ground rotational band in 82Sr\, 83Y\, 84Zr \, 85Nb\, 85Zr and 86Zr have been measured in order to study the dependenc e of quasi-particle alignment on the proton and neutron numbers. \nThe hig h spin states of the ground rotational band in 82Sr\, 83Y\, 84Zr\, 85Nb\, 85Zr and 86Zr were populated by the fusion-evaporation reactions with the heavy ion beams from the HI-13 tandem accelerator at China Institute of At omic Energy. The transient -magnetic-field ion implantation perturbed angu lar distribution (TMF-IMPAD) method was used to determine the g-factors of high spin states along the ground rotational band. The model calculations were also carrried out for some nuclides\, which well reproduced the expe rimentally measured g factors.\n\nThe experimental results are shown in th e above figure. It can be seen that for the nuclides 84Zr\, 85Zr and 86Zr with Z=40 the proton alignment is followed by the neutron alignment in 84Z r and 85Zr\, while the neutron alignment is followed by the proton alignme nt in 86Zr\, and for the nuclides 82Sr\, 83Y\, 84Zr and 85Nb with N=44 the proton aligns only in 82Sr\, the proton aligns first that is followed by the neutron alignment in 83Y and 84Zr and the neutron alignment is followe d by the proton alignment in 85Nb. A discussion regard the observed depend ence will be presented.\n\n*Supported by National Science Foundation of Ch ina under Grant Nos. 10435010 and 10975189\n** Corresponding author\n\nhtt p://indico.cern.ch/contributionDisplay.py?contribId=35&sessionId=4&confId= 30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=35&sessionId=4& confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Phonon mode softening at the ferroelectric transition in EuxBa1-xT iO3 DTSTART;VALUE=DATE-TIME:20100915T095000Z DTEND;VALUE=DATE-TIME:20100915T101000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-63@cern.ch DESCRIPTION:Speakers: Prof. CADOGAN\, Sean (University of Manitoba)\n151Eu Mössbauer study of phonon softening in ferroelectric EuxBa1-xTiO3.\n\nht tp://indico.cern.ch/contributionDisplay.py?contribId=63&sessionId=14&confI d=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=63&sessionId=14 &confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:CONCLUSION DTSTART;VALUE=DATE-TIME:20100917T101000Z DTEND;VALUE=DATE-TIME:20100917T103000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-178@cern.ch DESCRIPTION:Speakers: HAAS\, Heinz (Instituto Tecnologico et Nuclear ITN)\ nhttp://indico.cern.ch/contributionDisplay.py?contribId=178&sessionId=21&c onfId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=178&sessionId=2 1&confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Perturbed Angular Correlation in Bio Systems DTSTART;VALUE=DATE-TIME:20100916T074000Z DTEND;VALUE=DATE-TIME:20100916T082000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-176@cern.ch DESCRIPTION:Speakers: Dr. HEMMINGSEN\, Lars (Dept. of Natural Sciences\, T he Royal Veterinary and Agricultural University)\nhttp://indico.cern.ch/co ntributionDisplay.py?contribId=176&sessionId=16&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=176&sessionId=1 6&confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:MuSR studies of High Tc supercondictivity in iron pnictides DTSTART;VALUE=DATE-TIME:20100916T070000Z DTEND;VALUE=DATE-TIME:20100916T074000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-175@cern.ch DESCRIPTION:Speakers: KLAUSS\, H. ()\nhttp://indico.cern.ch/contributionDi splay.py?contribId=175&sessionId=7&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=175&sessionId=7 &confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Synchrotron radiation based TDPAC DTSTART;VALUE=DATE-TIME:20100915T091000Z DTEND;VALUE=DATE-TIME:20100915T095000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-174@cern.ch DESCRIPTION:Speakers: SERGUEEV\, I. ()\nhttp://indico.cern.ch/contribution Display.py?contribId=174&sessionId=14&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=174&sessionId=1 4&confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Development and applications of a Mössbauer camera DTSTART;VALUE=DATE-TIME:20100915T074000Z DTEND;VALUE=DATE-TIME:20100915T082000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-173@cern.ch DESCRIPTION:Speakers: Mr. YUTAKA\, Yoshida ()\nWe developed a mapping tech nique for 57Fe Mössbauer spectroscopy using a Multi-Capillary X-ray lens (MCX or Soejima-Kumakhov lens)\, which provided a space resolution down to 50m [1\, 2]. There are\, however\, strong demands to study sub-microme ter-scale structures in materials science. Presently\, we are challenging to improve the space resolution using a Fresnel-Zone Plate (FZP)\, which i s known to provide a possibility to focus X-ray beam down to several 10 nm in diameter\, if one would use it at a beam line of synchrotron facilitie s where a strong and sharp X-ray beam is available. In our laboratory\, th erefore\, we combine a FZP with the MCX in order to focus 14.4keV -rays down to hundreds nanometers. The focal distance is 48 mm from the outlet of FZP lens. The experimental or and 3.7 GBq-57Co source mounted on a Mös sbauer transducer. In order to evaluate the spot size of the combined - ray lens\, the transmission counts of 14.4keV -rays are measured as fun ctions of the X or Y positions of the Ta-knife-edge collimators by a Si-PI N detector. The measuring time is 55000 sec at each position. After subtra cting the background from the original data (red points in Fig.2)\, we obt ained the blue data points which shows two sharp peaks of the 1st order di ffraction at around 155m close to the beam center. In addition\, two br oad peaks appear at around 125 and 75 m\, which correspond to the 2nd o rder diffractions. The position of the Ta knife-edge appears to be about 1 0m deviated to the direction of the FZP from the exact focal position. Considering the focusing geometry and the half-width of the sharp peaks\, the spot size expected at the focal position can be estimated about 3m in diameter. The mapping images will be shown in the lecture.\n\nhttp://in dico.cern.ch/contributionDisplay.py?contribId=173&sessionId=13&confId=3090 2 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=173&sessionId=1 3&confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Beta detected NMR: a New Depth-resolved Probe of Materials at the Nanoscale DTSTART;VALUE=DATE-TIME:20100915T070000Z DTEND;VALUE=DATE-TIME:20100915T074000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-172@cern.ch DESCRIPTION:Speakers: Prof. MACFARLANE\, W. A. (Department of Chemistry\, University of British Columbia\, Vancouver\, BC\, Canada V6T 1Z1)\nhttp: //indico.cern.ch/contributionDisplay.py?contribId=172&sessionId=11&confId= 30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=172&sessionId=1 1&confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:MSR in Diamond DTSTART;VALUE=DATE-TIME:20100914T070000Z DTEND;VALUE=DATE-TIME:20100914T074000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-171@cern.ch DESCRIPTION:Speakers: CONNELL\, Simon (Brookhaven National Laboratory (BNL )-Unknown-Unknown)\nhttp://indico.cern.ch/contributionDisplay.py?contribId =171&sessionId=10&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=171&sessionId=1 0&confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Investigations on thin Fe films and Heusler alloy films using sync hrotron-radiation-based Mössbauer spectroscopy DTSTART;VALUE=DATE-TIME:20100914T074000Z DTEND;VALUE=DATE-TIME:20100914T080000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-184@cern.ch DESCRIPTION:Speakers: Prof. MIBU\, Ko (Nagoya Institute of Technology)\nRe cent development in synchrotron-radiation-based nuclear resonant scatterin g or Mössbauer spectroscopy has opened up new aspects on investigation of materials in the measurements of hyperfine interactions and also of local phonon density-of-states. In Japan a five-year project led by Prof. Seto at Kyoto University is now in progress for further development of these un ique techniques. The field of magnetic thin films is also getting a benefi t from these new techniques through detection of magnetic hyperfine fields . The method which has mainly been used so far for thin film experiments i s "time domain" measurements\, where interference patterns of pulsed X-ray s resonantly scattered by nuclei are detected as a function of time. Howev er\, "energy domain" measurements are more desirable for thin films\, whic h often contain inhomogeneity in the nuclear environments. In our project\ , a new synchrotron-radiation-based "energy domain" Mössbauer spectroscop ic method has been developed\, and optimize\n\nhttp://indico.cern.ch/contr ibutionDisplay.py?contribId=184&sessionId=10&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=184&sessionId=1 0&confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Measuring the magnetic properties of monolayers of single molecule magnets DTSTART;VALUE=DATE-TIME:20100914T130000Z DTEND;VALUE=DATE-TIME:20100914T132000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-97@cern.ch DESCRIPTION:Speakers: Dr. SALMAN\, Zaher (Laboratory for Muon Spin Spectro scopy\, Paul Scherrer Institut\, CH-5232 Villigen PSI\, Switzerland)\nte xt\n\nhttp://indico.cern.ch/contributionDisplay.py?contribId=97&sessionId= 12&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=97&sessionId=12 &confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Recent advances in Emission Channeling measurements and relevance to Hyperfine Interactions DTSTART;VALUE=DATE-TIME:20100916T091000Z DTEND;VALUE=DATE-TIME:20100916T093000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-185@cern.ch DESCRIPTION:Speakers: Dr. CORREIA\, J.G. (ITN\, Sacavem\, Portugal)\nHyper fine interactions are due to the coupling of the nuclear quadrupole and ma gnetic moments with the electric field gradient and magnetic fields presen t inside a material\, respectively. “Hyperfine Techniques” can then de liver unique information to enlighten atomic and electronic phenomenology on a nanoscopic scale\, provided their signal will be fitted with the righ t model and then properly interpreted. During the last two decades big adv ances have been made for the interpretation of hyperfine data. Powerful fi rst principle calculation methods of charge densities in materials provide today reliable tools for the interpretation of hyperfine parameters. Stil l\, these methods rely on establishing an atomic model with the only input of the initial atomic coordinates\, which are then allowed to relax to mo re energetically favorable positions. This brings us to the point that\, s ince the hyperfine parameters are extremely sensitive to both relaxations and the atomic position of the probing atom\, a technique that can provide precise local scale information about impurity element position can be of great use for the modeling of the atomic configurations used to interpret the hyperfine parameters.\nThis talk introduces the emission channeling ( EC) technique\, which uses the fact that charged particles (in this case e lectrons)\, emitted from implanted radioactive isotopes\, are guided by th e potential of atomic rows and planes while traveling through a single cry stal. The resulting anisotropic electron emission patterns around low-inde x crystal directions are characteristic for the lattice site occupied by t he emitting atom and are measured with a 2-dimensional energy- and positio n-sensitive Si detector of 22 × 22 pixels. This technique allows one to m easure the lattice location of a very low concentration of impurities with accuracy down to 0.1 Å. The combination of position sensitive detectors developed at CERN in the frame of high-energy particle detection with the ISOLDE radioactive beam facility provides a huge number of radioactive ele ment probes to be measured with high precision. Selected case study exampl es will be shown as well as the perspectives for improving this technique with new highly pixilated electron detectors recently developed at CERN.\n \nhttp://indico.cern.ch/contributionDisplay.py?contribId=185&sessionId=11& confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=185&sessionId=1 1&confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Precise Nuclear Moments of Extremely Proton-Rich Nuclei 23Al DTSTART;VALUE=DATE-TIME:20100916T093000Z DTEND;VALUE=DATE-TIME:20100916T095000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-98@cern.ch DESCRIPTION:Speakers: Dr. NAGATOMO\, Takashi (International Christian Univ ersity)\nNuclear magnetic moment µ and the electric quadrupole moment Q o f the ground state of 23Al have been measured precisely by the β-NMR/NQR technique.\n\nhttp://indico.cern.ch/contributionDisplay.py?contribId=98&se ssionId=4&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=98&sessionId=4& confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Recent Progress on Low Temperature Nuclear Orientation Technique a nd NMRON DTSTART;VALUE=DATE-TIME:20100913T075500Z DTEND;VALUE=DATE-TIME:20100913T083500Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-169@cern.ch DESCRIPTION:Speakers: SEVERIJNS\, Nathal ()\nhttp://indico.cern.ch/contrib utionDisplay.py?contribId=169&sessionId=4&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=169&sessionId=4 &confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Calculations of Hyperfine parameters in solids based on DFT and us ing WIEN2k DTSTART;VALUE=DATE-TIME:20100917T070000Z DTEND;VALUE=DATE-TIME:20100917T074000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-95@cern.ch DESCRIPTION:Speakers: BLAHA\, Peter (TU Vienna)\nI will review briefly the underlying concepts of electronic structure calculations in solids and mo re specifically describe density functional theory and the APW+lo method a s implemented in the WIEN2k code [1]. Special emphasis will be given to ex plain the calculations of isomer shifts\, magnetic hyperfine fields and el ectric field gradients (EFG) and in particular I’ll discuss how we can i nterpret the results and what we can learn from a particular hyperfine par ameter. For the case of several fluoro-aluminates I’ll demonstrate the s trong dependency of the EFG (and even more of the asymmetry parameter   on the exact atomic positions\, which makes it mandatory to optimize t he internal coordinates since often the experimentally determined position s are not accurate enough [2]. Mössbauer spectroscopy is also a very valu able tool to study matter under extreme conditions and recently [3] we cou ld explain the large change of the EFG with pressure in (Mg\,Fe)SiO3\, a v ery important material in the lower mantle of the earth. Finally I’ll di scuss EFGs\, isomer shifts and hyperfine fields in YBaFe2O5 (Fig.1)\, a ma terial which exhibits a Verwey transition between a charge-ordered and val ence-mixed state [4] with temperature. During this transition the crystal structure\, the magnetic order\, the charge state and the hyperfine parame ters change dramatically.\n\nhttp://indico.cern.ch/contributionDisplay.py? contribId=95&sessionId=19&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=95&sessionId=19 &confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:The Concept of Trajectories in the Data Analysis of Non-axially Sy mmetric Nuclear Quadrupole Interactions DTSTART;VALUE=DATE-TIME:20100913T132000Z DTEND;VALUE=DATE-TIME:20100913T134000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-15@cern.ch DESCRIPTION:Speakers: Prof. BUTZ\, Tilman (University of Leipzig)\nThe nuc lear quadrupole interaction is described as the product of the nuclear qua drupole moment Q with the electric field gradient (EFG) tensor. This is a symmetric\, trace-less 3x3 tensor which usually is described by two quant ities in the principle coordinate system: the largest component by magnitu de is denoted by Vzz and the asymmetry parameter is defined as h = (Vxx – Vyy)/Vzz. Frequently\, these two quantities are determined for powder samples as a function of an external variable\, e.g. temperature. It is cu stomary to plot both quantities separately versus temperature. This\, howe ver\, masks any eventual interdependencies of the two quantities. A better way to plot the results is to plot Vzz and Vxx in a carthesian plot\, or better in a Czjzek-plot [1]\, a variant of the carthesian plot\, which is still linear in both variables. Each data pair of Vzz/Vxx constitutes a p oint in this plot with temperature being the implicit parameter. Connectin g all points by a continuous line yields a trajectory. This trajectory is continuous even when passing over h = 1 where the tensor orientation flips by 90° and the sign of Vzz changes. \nInterestingly enough\, there are m any examples where a straight trajectory is observed\, i.e. both variables depend linearly on each other. This can be modelled by a linear superposi tion of two tensors which are simultaneously diagonal and temperature inde pendent: \nV = V1 + a(T)V2.\nThe only temperature dependent quantity is a( T)\, the control parameter. In this situation it is clear that fitting 2n independent parameters for n temperature points is wrong. Instead\, a scal e factor and a slope should be fitted in addition to n values for a(T)\ , i.e. there are n+2 independent parameters only. The slope is given by th e asymmetry parameter of V2\, which is the asymptotic asymmetry parameter of V for large a. V2 must have a physical interpretation\, contrary to V1 which can be modified by shifting a (unless we know where a must be 0\, i. e. if a is an order parameter). The temperature dependence of a contains a ll solid state information like lattice expansion\, lattice vibrations\, a nd changes in the electronic charge density distribution.\nThe correct str ategy for the data analysis would be to analyze the data conventionally\, plot the data in the Czjzek-plot\, and for a straight trajectory perform a simultaneous fit of all data with n+2 adjustable parameters in a second t ier.\nAnother interesting class of systems can be described by a linear su perposition of two tensors which are not simultaneously diagonal in the sa me principle coordinate system but which share one common coordinate aroun d which the other two rotate. In other words\, only a 2x2 matrix has to be diagonalized. The structure of the resulting eigenvalues (Vieta’s formu la) is such that by using the sum and the product of both the control para meter can be eliminated straightforwardly and second order curves result w hich must be hyperbolae because we require asymptotes. In this case we req uire n+3 adjustable parameters\, i.e. a scale factor\, the asymptotic asym metry parameter and one off-diagonal element which describes the rotation in addition to n values for a. Again\, a simultaneous fit of all data is r equired in a second tier.\nExamples of experiments with linear and hyperbo lic trajectories will be given.\n\n[1] G. Czjzek\, Hyperf\, Interact. 14\, 184\, (1984)\; T. Butz et al.\, Physica Scripta 54\,234\, (1996) \n\nOral presentation\n\nhttp://indico.cern.ch/contributionDisplay.py?contribId=15& sessionId=11&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=15&sessionId=11 &confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Anomalous Magnetism and 209Bi Nuclear Spin Relaxation in Bi4Ge3O12 Crystals DTSTART;VALUE=DATE-TIME:20100916T132000Z DTEND;VALUE=DATE-TIME:20100916T134000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-18@cern.ch DESCRIPTION:Speakers: Prof. ORLOV\, Valery (Russian Research Center "Kurch atov Institute"\, Moscow 123182\, Russia)\nUnique magnetic properties wer e earlier found by measuring the NQI parameters in a number of bismuth (II I) oxy compounds with s- and p-electrons hitherto classified as diamagneti c [1]. In α-Bi2O3 single crystal the magnetoelectric effect and paramagne tism depending on magnetic prehistory of the sample were observed [1]. \n In Bi4Ge3O12 (BGO)\, local magnetic fields (Hloc) of the order of 20 -30 G were found by modeling the Zeeman split 209Bi NQR spectra and spin-e cho envelope [2-3]. A dramatic increase in the 209Bi line intensity was ob served for this compound in the Zeeman fields (He ) hence revealing a rema rkable elongation of the nuclear spin-spin relaxation time T2 under the in fluence of He [4]. This stimulated relaxation studies of the BGO crystals doped with the “magnetic” atoms Cr\, Nd\, Pr\, Gd.\n Here\, we p resent the results of a study of the 209Bi nuclear quadrupole spin-spin an d spin-lattice relaxation in pure and doped BGO single crystals in the tem perature range 4.2300 K. \n Various mechanisms (quadrupole\, crys tal electric field\, electron spin fluctuations) governing the temperature dependence of the spin-lattice relaxation time T1 in pure and doped sampl es at different temperature ranges are considered. \n Unlike T1\, the spin-spin relaxation time T2 for pure and Nd-doped samples only weakl y depended on temperature over the whole temperature range studied. Doping BGO with paramagnetic atoms strongly elongated T2\, the elongation being also observed under the influence of weak external magnetic fields.\n The magnetization of doped BGO crystals vs. magnetic field and temperatur e was measured using a SQUID magnetometer. The temperature behavior of mag netic susceptibility for the Nd-doped BGO crystal evidenced for the presen ce of the crystal electric field effects. The curves of magnetization vs. magnetic field measured for the Gd-doped BGO crystal under field cooling a nd zero-field cooling conditions were markedly different\, although this d ifference was less pronounced than that for the α-Bi2O3 crystal [1].\nRef erences \n[1] E.A. Kravchenko\, V.G. Orlov\, and M.P. Shlykov\, Russian Ch em. Rev. 75\, 77 (2006). \n[2] E.A. Kravchenko\, Yu.F. Kargin\, V.G. Orlov \, T. Okuda\, K. Yamada\, JMMM\, 224\, 249 (2001). \n[3] E.A. Kravchenko\, V.G. Orlov\, V.G. Morgunov\, M.P. Shlykov\, Hyperfine Interact. 180\, 437 (2007). \n[4] E.A. Kravchenko\, V.G. Morgunov\, V.G. Orlov\, Yu.F. Kargin \, JETP Letters. 86\, 390 (2007).\n\nhttp://indico.cern.ch/contributionDis play.py?contribId=18&sessionId=12&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=18&sessionId=12 &confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Magnetism in Iron Implanted Oxides: A Status Report DTSTART;VALUE=DATE-TIME:20100914T091000Z DTEND;VALUE=DATE-TIME:20100914T095000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-151@cern.ch DESCRIPTION:Speakers: Dr. SIELEMANN\, Rainer (Helmholtz-Zentrum Berlin fü r Materialien und Energie\, D-14109 Berlin\, Germany)\nDiluted magnetic se miconductors form a special class of magnetic materials which has drawn a lot of attention over the last years both for the interest in the basic ph ysics involved and for possible applications\, e.g.\, in the field of spin tronics. However\, there is no general agreement on the origin of this typ e of magnetism. Various coupling mechanisms between the magnetic ions have been proposed\, in addition the role of intrinsic defects as well as of u nintentional magnetic impurities and precipitations was considered. Oxide s with embedded magnetic ions form a subclass of the magnetic semiconducto rs. To study magnetism at the atomic level Mössbauer spectroscopy (MS) ca n be utilized\, especially with 57Fe. Since the solubility of 3d magnetic ions in most semiconductors is small\, their introduction is difficult. So \, implantation is a favorable technique. In addition it creates intrinsic defects and thus may influence (create) magnetic phenomena. With this ide a in mind 57Fe MS was performed at the ISOLDE facility at CERN following i mplantation of radioactive 57Mn (T1/2 = 1.5 min) in diverse oxides with a focus on ZnO\, one of the most important materials for magnetic semiconduc tors [1]. The Mössbauer spectra obtained consist to a large part of a mag netic sextet with splitting up to about 50 T and in addition of nonmagneti c components indicating different lattice sites and/or charge states of th e Fe atoms. Surprisingly the sextet persists up to measuring temperatures of about 600 K. Experiments performed on other oxides (e.g.\, MgO\, Al2O3) show results with partly similar and partly differing features. Detailed MS studies as function of temperature\, implanted Mn concentration\, pre-d oping of the oxides with various magnetic and nonmagnetic ions and in part icular experiments with an external magnetic field of 0.6 T show a variety of phenomena with respect to the occurrence of the magnetic fraction and permit attributing it to Fe-ions in a 3+ paramagnetic state. This observat ion of a static magnetic pattern is enabled by the unusually long relaxati on time > 20 ns even at 600 K though this relaxation time normally strongl y decreases with rising temperature. Unlike a first report [2] there is pr esently no necessity to involve ordered magnetism in the interpretation of the magnetic spectra [3]. The assets of MS in these studies compared to\, e.g.\, the EPR technique (Electron Paramagnetic Resonance) will be discus sed. References [1] T. Dietl et al.\, Science 287\, 1019 (2000). [2] G. Weyer et al.\, J. Appl. Phys. 102\, 113915 (2007). [3] H.P. Gunnlaugsson et al.\, Appl. Phys. Lett. (manuscript in preparation).\n\nhttp://indico. cern.ch/contributionDisplay.py?contribId=151&sessionId=12&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=151&sessionId=1 2&confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Density of Phonon States at the Fe Sites in Superconducting FeSe as Function of Temperature and Pressure DTSTART;VALUE=DATE-TIME:20100915T101000Z DTEND;VALUE=DATE-TIME:20100915T103000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-150@cern.ch DESCRIPTION:Speakers: Prof. WORTMANN\, Gerhard (2Department Physik\, Unive rsität Paderborn)\nThe temperature and pressure dependence of the partial density-of-phonon states (phonon-DOS) at the iron sites in superconductin g (sc) Fe1.01Se was studied by 57Fe nuclear inelastic scattering (NIS) of synchrotron radiation\, a method well adapted for these studies as functio n of temperature and pressure [1\,2]. As proved by a recent study of the i sotope effect at the Fe sites on the sc temperature Tc in FeSe\, supercond uctivity is intrinsically connected with the Fe phonon modes [3]. The sc p roperties of the present Fe1.01Se sample and their pressure dependencies w ere well characterized in previous studies using various methods\, includi ng 57Fe-Mössbauer spectroscopy [4-7]. The high energy resolution in the p resent 57Fe-NIS study allows for a detailed observation of spectral proper ties in the phonon-DOS not observed before\, e.g. shifts of all spectral f eatures to higher energies by ~4% with decreasing temperature from 296 K t o 10 K. No detectable changes in the partial Fe phonon-DOS were observed a t the tetragonal–orthorhombic transition around 100 K [7\,8]. An applie d pressure of 6.7 GPa\, combined with an increase of the sc temperature T c from 8 K to 34 K [8]\, resulted in an increase of the optical phonon-mod e energies by ~12%\, and an even more pronounced increase in energies of t he lowest-lying transversal acoustic modes. Despite of these strong pressu re-induced changes in the partial Fe phonon-DOS we conclude that the prono unced increase of Tc in Fe1.01Se with pressure cannot be described in the framework of classical electron-phonon coupling [8]. This suggests the imp ortance of spin fluctuations for the observed superconductivity [9]. The p resent results are discussed in conjunction with the phonon-DOS of FeSe0.5 Te0.5 X-tals\, studied including its polarization dependence by 57Fe-NIS [ 10]\, where Tc = 15 K was observed at ambient pressure. Finally we present a synopsis of the complementary information on the sc Fe1.01Se and FeSe0. 5Te0.5 systems\, obtained from the elastic channel\, 57Fe-ME [4-7]\, as we ll as from the inelastic channel\, 57Fe-NIS [8\, 10]\, of the 57Fe(14.4 keV)-Mössbauer resonance. References: * wortmann@physik.upb.de [1] A .I. Chumakov et al.\, Phys. Rev. B 54\, R9596 (1996). [2] R. Lübbers\, H. F. Grünsteudel\, A.I. Chumakov\, G. Wortmann\, Science 287\, 1250 (2000). [3] R. Khasanov et al.\, arXiv:1002.2510.v1. [4] T.M. McQueen et al.\, Phys. Rev. B 79\, 014522 (2009). [5] S. Medvedev et al.\, Nature Mater. 8\ , 630 (2009). [6] V. Ksenofontov et al.\, contribution to this conference. [7] T.M. McQueen et al.\, Phys. Rev. Lett. 103\, 057002 (2009). [8] V. Ks enofontov et al.\, Phys. Rev. B (in print)\; see arXiv:1004.2007. [9] T. Imai et al.\, Phys. Rev. Lett. 102\, 177005 (2009). [10] V. Ksenofontov\, G. Wortmann\, T. Gasi\, J. Deisenhofer\, V. Tsurkan\, C. Felser (unpublish ed)\n\nhttp://indico.cern.ch/contributionDisplay.py?contribId=150&sessionI d=14&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=150&sessionId=1 4&confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Perturbed angular correlation study of the magnetic and structural first-order phase transition in MnAs DTSTART;VALUE=DATE-TIME:20100916T130000Z DTEND;VALUE=DATE-TIME:20100916T132000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-155@cern.ch DESCRIPTION:Speakers: GONÇALVES\, J. N. (Departmento de Física and CICEC O\, Universidade de Aveiro\, 3810-193 Aveiro\, Portugal)\ntext + reference s\n\nhttp://indico.cern.ch/contributionDisplay.py?contribId=155&sessionId= 12&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=155&sessionId=1 2&confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Magnetism in Azurite Studied by Muon Spin Rotation DTSTART;VALUE=DATE-TIME:20100914T124000Z DTEND;VALUE=DATE-TIME:20100914T130000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-46@cern.ch DESCRIPTION:Speakers: LITTERST\, Jochen (TU Braunschweig)\nThe natural min eral azurite Cu3(CO3)2(OH)2 represents a new type of low-dimensional frust rated quantum spin system with a diamond spin chain as basis. From specifi c heat [1] there is evidence for a phase transition at ca. 1.8 K which how ever is magnetically still ill-defined. Earlier muon spin rotation experim ents [2] have indicated a magnetic transition yet no systematic study has been reported. We have performed zero field and transverse field muon spin rotation experiments at Paul Scherrer Institut Villigen (Switzerland) in the temperature range from 0.02 K to 6 K on polycrystalline powder and a s ingle crystal. We could corroborate the appearance of magnetic order below 1.9 K from spontaneous muon spin rotations with frequencies following a m agnetization curve indicating 2-dimensional correlations. There is evidenc e for a further change in magnetic structure below about 500 mK. The order ed magnetic Cu moments can be estimated to be only on the order of some te nths of a Bohr magneton in agreement with recent neutron scattering data [ 3]. \n\nReferences\n[1] H. Kikuchi\, et al.\, Phys. Rev. Lett. 94\, 227201 (2005).\n[2] H. Kikuchi\, et al.\, Progress of Theoretical Physics Supplem ent. 159\, 1 (2005)\n[3] K. Rule\, et al.\, Phys. Rev. B 81 in print (2010 )\n\nhttp://indico.cern.ch/contributionDisplay.py?contribId=46&sessionId=1 2&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=46&sessionId=12 &confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Recent Methodological Developments in Nuclear Resonant Scattering with Synchrotron Radiation DTSTART;VALUE=DATE-TIME:20100914T082000Z DTEND;VALUE=DATE-TIME:20100914T084000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-86@cern.ch DESCRIPTION:Speakers: Dr. ALP\, Esen Ercan (Argonne National Laboratory)\n A review of progress made in synchrotron radiation based techniques\n\nhtt p://indico.cern.ch/contributionDisplay.py?contribId=86&sessionId=11&confId =30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=86&sessionId=11 &confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Electric field gradient calculations by quantum chemical methods DTSTART;VALUE=DATE-TIME:20100917T091000Z DTEND;VALUE=DATE-TIME:20100917T094000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-43@cern.ch DESCRIPTION:Speakers: Prof. KELLOE\, Vladimir (Comenius University Bratisl ava)\nThe electric field gradient\, which from the point of view of the gi ven nucleus is a measure of the inhomogeneity of the external electric fie ld of all other charges\, is a molecular property of the first order and c an be determined from the knowledge of the electronic wave function and po sitions of nuclei. Since for accurate calculations we have to use highly s ophisticated electron correlation approximations like the Coupled Cluster Singles and Doubles with non-iterative Triples CCSD(T) method\, which does not fulfill the Hellmann-Fyenman theorem\, and therefore we are forced to use so-called derivatives methods instead of calculating the expectation value of the given operator. Inclusion of relativistic effects in calculat ion of electric field gradients is inevitable [1]. If one– or two–comp onent relativistic methods (e.g. DKH\, IOTC) are exploited\, the usual met hod of computing\, which is just a counterpart of the nonrelativistic sche me leads to the change of picture effect [2] manifested by significant ina ccuracies of the calculated property values. Different techniques how to a void the change of picture effect will be discussed [3-5].\nThe combinatio n of experimental nuclear quadrupole coupling constant obtained from micro wave spectra and theoretical electric field gradient provides currently th e best source of nuclear quadrupole moment values\, at least for light ele ments. A series of such determinations of nuclear quadrupole moments will be presented [6-11].\nReferences:\n[1] M. Iliaš\, V. Kellö\, M. Urban\; Acta Phys. Slovaca\, in press.\n[2] V. Kellö\, A. J. Sadlej\; Int. J. Qua ntum Chem.\, 68\, 159 (1998).\n[3] M. Pernpointner\, M. Seth\, P. Schwerdt feger\; J. Chem. Phys.\, 108\, 6722 (1998).\n[4] V. Kellö\, A. J. Sadlej\ ; J. Chem. Phys.\, 112\, 522 (2000).\n[5] V. Kellö\, A. J. Sadlej\; J. Ch em. Phys.\, 120\, 9424 (2004).\n[6] V. Kellö\, A. J. Sadlej\, P. Pyykkö\ , D. Sundholm\, M. Tokman\; Chem. Phys. Letters\, 304\, 414 (1999).\n[7] V . Kellö\, A. J. Sadlej\; Mol. Phys.\, 96\, 275 (1999).\n[8] V. Kellö\, P . Pyykkö\, A. J. Sadlej\, P. Schwerdtfeger\, J. Thyssen\; Chem. Phys. Let ters\, 318\, 222 (2000).\n[9] J. Bierroń\, P. Pyykkö\, D. Sundholm\, V. Kellö\, A. J. Sadlej\; Phys. Rev A\, 64\, 052507 (2001).\n[10] L. Demovi č\, V. Kellö\, A. J. Sadlej\, S. A. Cooke\; J. Chem. Phys.\, 124\, 18430 8 (2006).\n[11] V. Kellö\, A. J. Sadlej\; Collect. Czech. Chem. Commun. 7 2\, 64 (2007).\n\nhttp://indico.cern.ch/contributionDisplay.py?contribId=4 3&sessionId=19&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=43&sessionId=19 &confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:DFT Study of Hyperfine Interactions in Some Types of the Complexes DTSTART;VALUE=DATE-TIME:20100916T122000Z DTEND;VALUE=DATE-TIME:20100916T124000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-1@cern.ch DESCRIPTION:Speakers: Prof. POLESHCHUK\, Oleg (Tomsk State Pedagogical Uni versity)\nIt is well known that chemical applications of the NQR and Möss bauer spectroscopies use the sensitivity of the experimental parameters to investigate changes in the electron density at the nucleus [1]. The nucle ar quadrupole constants and isomer shift are a function of both nuclear an d electronic properties of the molecular systems\, which are combined in s uch a way that independent quantitative information on both kinds of prope rties cannot be obtained by NQR and Mössbauer spectroscopy alone. Since t he electronic properties are usually of interest and because the nuclear p arameters are constant\, the hyperfine parameters are most frequently used to compare the electronic properties of different molecules. The covalent effects and the shielding of one set of electrons by another also influen ce the electronic environment of the nucleus and may be reflected in chang es in the isomer shift. On the other hand central to most simple theories of Lewis acidity is the idea that both ionic and covalent interactions pla y important roles in stabilizing the donor-acceptor bond [2]. \nIn this re port\, we present a DFT calculations based on a microwave spectroscopic\, nuclear quadrupole resonance and Mössbauer shifts of the donor-acceptor c omplexes formed from metal halides such as PtCl2\, PtCl4\, XeF2\, AuCl\, A uCl3\, SbCl5\, SnF4\, SnCl4\, TiCl4\, SnBr4\, NbCl5\, TaCl5 \, halogens an d interhalogens with organic ligands. All ligands have a different basicit y and softness. Therefore\, it is of interest to investigate these complex es with a different acids and to compare their structural and electronic p roperties. \nThe full optimization of geometry was carried out using B3LYP achieved within the GAUSSIAN’03 program. The calculations of the comple xes were carried out with all-electron DGDZVP basis set. The quadrupole co upling constants of the quadrupole atoms and the formation energy of the c omplexes has been broken down using the extended transition state (ETS) sc heme implemented in the ADF package. We have used the OPTX exchange functi onal combined with PBE correlation functional with an uncontracted STO tri ple- + polarization basis set using the frozen core approximation to tr eat the inner electrons. There are bases to consider\, that the relativist ic effects basic for such heavy atoms should be considered by the zero ord er regular approximation (ZORA) that is more reliable than the widely used Pauli formalism. \nAn analysis of the quality of the calculations that em ploy all-electron basis set for the halogen compounds was carried out. The ZORA method is shown to be a viable alternative for the calculation of ha logen coupling constants in molecules. In addition\, the ZORA model\, in c ontrast to the pseudo-potential model\, leads to realistic values of all m etal nuclear quadrupole coupling constants [3]. \nThe calculated energy te rms can be identified with three main components of the chemical bond\, i. e. Pauli repulsion\, electrostatic attraction and covalent interaction. As a result\, we receive the answer to a question about the relative contrib utions of covalent and electrostatic interactions to the donor-acceptor bo nd. If for the transition element complexes the electrostatic bonding is l arger than covalent bonding while for the non-transition element complexes the tendency opposite. The obtained result will be coordinated to the con clusion on the basis of Klopman approach.\nIn the language of the theory o f hard and soft acids and bases\, the calculated energy gaps involve direc t mixing of the donor and acceptor orbitals. Energy of the bonds\, calcula ted from the general energy of molecules with ZPE corresponded as formatio n energy of the ETS scheme\, and to experimental enthalpy of the complex f ormation. The obtained dependences between Mössbauer chemical shifts and populations of the central atoms pointed to another nature of the chemical shifts in transition compounds in comparison with non-transition element compounds. \n Besides\, the values of the valence electron charge density at the nucleus 0 have been evaluated from ZORA calculations for a numb er of Au\, Pt\, Xe\, Sn\, Sb\, I compounds in order to check the accuracy of the theoretical approach. The linear correlations between the experimen tal values of δ and the calculated values of 0 is obtained.\n\n[1]. Pa rish R. V. Coord. Chem. Rev.\, 1982\, V. 42\, P. 1.\n[2] Frenking G.\, Wic hmann K. et al. Coord. Chem. Rev.\, 2003\, V. 238-239\, P. 55.\n[3] Polesh chuk O. K.\, Branchadell V.\, Ritter R. A.\, Fateev A. V. Hyperfine Intera ctions\, 2008\, V. 181\, No. 1-3\, P. 27.\n\nhttp://indico.cern.ch/contrib utionDisplay.py?contribId=1&sessionId=19&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=1&sessionId=19& confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:A-priori calculations of hyperfine interactions in highly ionized atoms: g-factor measurements of pico-second states populated in nuclear re actions. DTSTART;VALUE=DATE-TIME:20100917T082000Z DTEND;VALUE=DATE-TIME:20100917T084000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-146@cern.ch DESCRIPTION:Speakers: STONE\, Nicholas (Oxford University/University of Te nnessee)\nreport of new calculation of hyperfine interactions in complex i ons applied to g-factor measurements\n\nhttp://indico.cern.ch/contribution Display.py?contribId=146&sessionId=19&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=146&sessionId=1 9&confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Muon spin relaxation studies of geometrically frustrated magnets DTSTART;VALUE=DATE-TIME:20100914T122000Z DTEND;VALUE=DATE-TIME:20100914T124000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-76@cern.ch DESCRIPTION:Speakers: Dr. DALMAS DE REOTIER\, Pierre (CEA Grenoble)\nSee b elow\n\nhttp://indico.cern.ch/contributionDisplay.py?contribId=76&sessionI d=12&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=76&sessionId=12 &confId=30902 END:VEVENT BEGIN:VEVENT SUMMARY:Mössbauer study of spin-lattice relaxations of dilute Fe3+ in MgO DTSTART;VALUE=DATE-TIME:20100914T095000Z DTEND;VALUE=DATE-TIME:20100914T101000Z DTSTAMP;VALUE=DATE-TIME:20130524T144015Z UID:indico-contribution-30902-47@cern.ch DESCRIPTION:Speakers: Mr. MØLHOLT\, Torben Esmann (University of Iceland) \nT. E. Mølholt1\, R. Mantovan2\, H. P. Gunnlaugsson3\, K. Bharuth-Ram4\, M. Fanciulli2\,5\, K. Johnston6\, Y. Kobayashi7\, G. Langouche8\, H. Mase nda9\, D. Naidoo9\, S. Ólafsson1\, \nR. Sielemann10\, G. Weyer3\, H. P. Gíslason1\n \n1Science Institute\, University of Iceland\, Reykjavík\, I celand\, e-mail: tem4@hi.is\; 2Laboratorio MDM-IMM-CNR\, Milano\, Italy\; 3Department of Physics and Astronomy\, Aarhus University\, Denmark\; 4Scho ol of Physics\, University of KwaZulu-Natal\, South Africa\; 5Dipartimento di Scienza dei Materiali\, Università di Milano Bicocca\, Milano\, Italy \; 6PH Dept\, ISOLDE/CERN\, 1211 Geneva 23\, Switzerland\; 7The Institute of Physical and Chemical Research\, Wako\, Japan\; 8Instituut voor Kern-en Stralingsfysika\, University of Leuven\, Belgium\; 9School of Physics\, U niversity of the Witwatersrand\, South Africa\; 10Helmholtz Zentrum\, Berl in\, Germany.\n\nWe have measured 57Fe emission Mössbauer spectra followi ng 50 – 60 keV implantation of radioactive 57Mn+ ( s) at the ISOLDE faci lity at CERN into MgO single crystals held at 77 – 647 K (Fig. 1). This method allows us to study Fe impurities in concentrations \n\nhttp://indic o.cern.ch/contributionDisplay.py?contribId=47&sessionId=12&confId=30902 LOCATION:CERN Main Auditorium URL:http://indico.cern.ch/contributionDisplay.py?contribId=47&sessionId=12 &confId=30902 END:VEVENT END:VCALENDAR