Speaker
Description
The number of metastable phases, the capriciousness at changing external conditions, and lack of accurate description of local behavior already resulted in severe misinterpretation of experimental outcomes for vanadium oxides[1–3]. The scope of already implemented and potential applications of vanadium oxides is, indeed, impressive, particularly as a battery cathode for energy storage[4].
Doping is widely exploited as a means of application-oriented tuning of the material properties. The properties of each particular phase may be tuned by doping to satisfy specific requirements and/or improve the functional performance. In the work here reported, electric quadrupole interaction on $^{111m}$Cd nuclei implanted in vanadium pentaoxide doped with different concentrations of Cd were measured with time-differential perturbed angular correlations (TDPAC).
Pure V$_2$O$_5$ as well as doped with 1%, 5%, and 10% of Cd were measured at different temperatures. To correlate the results with the possible formation of different phases and compounds, samples of VO$_2$, CdV$_2$O$_6$, and Cd$_2$V$_2$O$_7$ were also measured. The intention is to provide a comprehensive description, at an atomic level, of the doping effects on the local crystal structure and the electronic structure around the impurity and the consequences on the properties of the host oxides. Preliminary results show that the probability of formation of cadmium vanadates is low but the temperature and atmosphere of measurements have an important effect on the local scale.
References
[1] A. Pergament, G. Stefanovich, and V. Andreeev, Comment on metal-insulator transition without structural phase transition in V$_2$O$_5$ film. Appl. Phys. Lett. 102, 176101 (2013), doi: 10.1063/1.4804203.
[2] M. Kang, I. Kim, S. W. Kim, J.-W. Ryu, and H. Y. Park, Metal-insulator transition without structural phase transition in V$_2$O$_5$ film. Appl. Phys. Lett. 98, 131907 (2011), doi: 10.1063/1.3571557.
[3] R.-P. Blum, H. Niehus, C. Hucho, R. Fortrie, M. V. Ganduglia-Pirovano, J. Sauer, S. Shaikhutdinov, and H.-J. Freund, Surface metal-insulator transition on a vanadium pentoxide (001) single crystal. Phys. Rev. Lett. 99, 226103 (2007), doi:10.1103/PhysRevLett.99.226103.
[4] P. Liu, K. Zhu, Y. Gao, H. Luo, and L. Lu, Recent Progress in the Applications of Vanadium-Based Oxides on Energy Storage: from Low-Dimensional Nanomaterials Synthesis to 3D Micro/Nano-Structures and Free-Standing Electrodes Fabrication. Adv. Energy Mater. 7, 1700547 (2017), doi: 10.1002/aenm.201700547.
