Vacancy Induced Magnetism in Tetragonal Structure ZrO<sub>2</sub> Based on First-Principles Study

Tetragonal zirconia (t-ZrO 2 ) has broad applications for structural ceramics, such as solid oxide fuel cells, electrolysis materials, membranes, and biomedical applications. However, its electronics and magnetics properties are rarely well studied. We carried out spin-polarized calculations to understand the vacancy characteristics in t-ZrO 2 . We apply neutral single Zr vacancy (V Zr ) and O vacancy (V O ) for supercell calculations up to 108 atoms. The calculated band gap of t-ZrO 2 is 3.81 eV, which becomes a narrowing band gap by V Zr . We find that both vacancies systems induce outward relaxations of atoms near vacancies, creating lower symmetry from pristine D 4h to D 2d and C 2v for V Zr and V O cases, respectively. The calculated magnetic moment V Zr is 4 mB due to four electrons of the valence band being occupied in the majority state. Four oxygen electrons of p -orbitals dominate the spin densities near V Zr . In contrast, the magnetic moment in the case of V O is 0 µB. Thus, since they have a high magnetic moment in the case of V Zr , t-ZrO 2 is potentially used as material for diluted magnetic semiconductors.