Feb 12 – 14, 2007
CERN
Europe/Zurich timezone

Local Ordering of Oxygen in High-Tc Superconductors

Feb 13, 2007, 4:45 PM
20m
Council Chamber, 503/1-001 (CERN)

Council Chamber, 503/1-001

CERN

Speaker

Tania Melo Mendonca (Departamento de Física, Instituto Tecnológico e Nuclear, ITN, E.N. 10, 2686-953 Sacavém, Portugal)

Description

Lattice sites and collective ordering of highly oxygen doped samples of HgBa2Can-1CunO2n+2+δ (n=2, 3, Hg-1212 and Hg-1223) were investigated using the Perturbed Angular Correlation (PAC) technique by measuring the electric field gradients at 199mHg nuclei. The experiments in these compounds were performed at different annealing conditions, under Ar flow or O2 pressure up to 152 bars. In comparison with the data and calculations already published for the fluorine doping in Hg-1201 (n=1) [1], the preliminary analysis hints that at high concentrations oxygen atoms order in different way, other than the atomic-like stripes found for fluorine. In addition, these experiments have been performed at different temperatures, above and below the superconducting transition, which have revealed further differences in the charge distribution of the Hg surroundings. A full set of PAC, magnetic and X-ray diffraction data has been obtained that is now being analyzed to be further compared to first principle calculations of charge density in these materials obtained for different oxygen configurations. [1] J. G. Correia, H. Haas, V. S. Amaral, A. M. L. Lopes, J. P. Aráujo, S. Le Floch, P. Bordet, E. Rita, J. C. Soares, W. Troger and the ISOLDE collaboration, Physical Rev. B 72 (2005) 1.

Primary author

Tania Melo Mendonca (Departamento de Física, Instituto Tecnológico e Nuclear, ITN, E.N. 10, 2686-953 Sacavém, Portugal)

Co-authors

André Pereira (Departamento de Física and IFIMUP, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal) Heinz Haas (Departamento de Física, Instituto Tecnológico e Nuclear E.N. 10, 2686-953 Sacavém, Portugal) João Amaral (Departamento de Física, Universidade de Aveiro, Campus Universitário de Santiago, 3810 Aveiro, Portugal) João Guilherme Correia (Departamento de Física, Instituto Tecnológico e Nuclear E.N. 10, 2686-953 Sacavém, Portugal) João Pedro Araujo (Departamento de Física and IFIMUP, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal) Manuel Ribeiro da Silva (Departamento de Física, Instituto Tecnológico e Nuclear E.N. 10, 2686-953 Sacavém, Portugal) Marcelo Pereira (Departamento de Física and IFIMUP, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal) Philippe Odier (Lab.Crystalographie, CNRS, Av. des Martyrs 25, F-38042 Grenoble CEDEX 9, France) Ricardo Ferreira (Departamento de Física, Instituto Tecnológico e Nuclear E.N. 10, 2686-953 Sacavém, Portugal)

Presentation materials