Magnetic and Electronic Properties of Point Defects in ZrO2

Using the Korringa-Kohn-Rostoker Coherent Potential Approximation (KKR-CPA) method in connection with the Generalized Gradient Approximation (GGA), we study the magnetic and electronic properties of different point defects in cubic ZrO2. In particular, we discuss the zirconium interstitial (Zr-i), zirconium antisite (Zr-O), zirconium vacancy (V-Zr), oxygen interstitial (O-i), oxygen antisite (O-Zr), and oxygen vacancy (V-O) defects. It has been shown that oxygen vacancy and zirconium interstitial (V-O, Zr-i) are n-type, while the other point defects are p-type. The magnetic moments are observed only in the oxygen interstitial and antisite (O-i, O-Zr) cases. The corresponding ferromagnetic states are more stable than the spin-glass states. It has been found that the mechanism responsible of such stabilities is the double exchange. Based on Mean Field Approximation (MFA), the Curie temperature (T-C) is estimated. Moreover, it has been found that the O-i and O-Zr defects provide half-metallic properties being the responsible for ferromagnetism.