INSTITUTO DE FISICA LA PLATA
Unidad Ejecutora - UE
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Theoretical calculations on the Electric Field Gradient in HfO2:Cd and ZrO2:Cd
M.A. TAYLOR; L.ERRICO; R.E. ALONSO
Conferencia; 3rd Joint International Conference on Hyperfine Interactions and International Symposium on Nuclear Quadrupole Interactions; 2010
Zirconia-based materials and HfO2 are in the focus of interest for many years due to their outstanding electrical and mechanical properties. HfO2 and ZrO2 are very similar in their crystallographic and electronic structure. They have three polymorphs at atmospheric pressure: their low-temperature phase is monoclinic, increasing the temperature they transform to a tetragonal phase, and finally to a cubic phase as temperature increases. In this work, we analyze de Electric Field Gradient (EFG) in the Cd site for the doped monoclinic structure of ZrO2 and HfO2. The theoretical results are compared with those determined experimentally by means of Perturbed Angular Correlation (PAC) spectroscopy. Our calculations are based on the Density Functional Theory (DFT), with the Local Density approximation (LDA) and the Generalized Gradient Approximation (GGA) for the exchange correlation potential, as implemented in the WIEN2k version of the Full Potential APW+LO. Different charge states for the Cd impurity are analyzed, and their influence on the hyperfine parameters.