Lattice distortion and its role in the magnetic behavior of the Mn-doped ZnO system

Abstract

Puzzling magnetic data on the Zn 1-xMn xO system such as a small magnetization values or a large negative values of the Curie-Weiss temperature have been obtained in many experimental investigations. Here we report element-specific structural and magnetic investigations on a highquality Zn 0.95Mn 0.05O nanocrystalline sample. Combining low-temperature x-ray absorption spectroscopy and theoretical simulations, we show that the formation of substitutional spin-antiparallel pairs induces a large local distortion involving a contraction of the Mn-Mn distance and a reduced Mn-O-Mn bond angle. The first-principles calculation considering hole-doping reveals that such a distortion can result in a localized hole around a dopant atom, generating a ferrimagnetic ordering with a magnetization of 0.45 μB/Mn. This result may give a new insight for a better understanding of the reported magnetic data. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.