Experimental and theoretical evidence for the presence of room temperature ferromagnetism in undoped and Mn doped tetragonal ZrO2 nanostructures

Abstract

The largest value of saturation magnetization is found for undoped t-ZrO2 and it decreases as Mn content increases. The experimental results are explained in terms of coupling constant ⿿J⿿ calculated using density functional theory (DFT). Oxygen-vacancy-mediated Zr⿿Zr ferromagnetic interaction (J=1.07kJ/mol) is found to be responsible for RTFM in undoped t-ZrO2 nanostructures. However, Mn doping induces antiferromagnetic interaction (J=⿿0.55kJ/mol) between Zr⿿Mn mediated by oxygen vacancies that essentially reduce ferromagnetism at (5at.%) doping and finally leads to the paramagnetic nature at 10at.% of Mn doping in ZrO2 matrix.