Structural, electronic and hyperfine properties and unexpected local magnetic moments in Ta-doped m-ZrO2 and m-HfO2

L. A. ERRICO

San Pablo

Conferencia; Conferencia invitada, Instituto de Física, Departamento de Materiales de la Universidad de San Pablo, Brasil.; 2011

CoInstituto de Física, Departamento de Materiales de la Universidad de San Pablo, Brasil.

A combination of experiments and ab initio quantum-mechanical calculations has been applied to examine electronic, structural and hyperfine interactions in pure and Ta-doped zirconium and hafnium dioxide in its monoclinic phase (m-Zr/HfO2). From the theoretical point of view, the full-potential linear augmented plane wave plus local orbital (APW+lo) method was applied to treat the electronic structure of the doped system including the atomic relaxations introduced by the impurities in the host in a fully self-consistent way using a supercell approach. Different charge states of the Ta impurity were considered in the study and it effects on the electronic, structural and hyperfine properties are discussed. Our results suggest that two different charge states coexist in Ta-doped m-Zr/HfO2. Further, ab initio calculations predict that, depending on the impurity charge state, a sizeable magnetic moment can be induced at the Ta-probe site. This prediction is confirmed by a new analysis of experimental data.