Magnetic coupling properties of rare-earth metals (Gd, Nd) doped ZnO: first-principles calculations

TL;DR

This study uses first-principles calculations to explore how doping ZnO with Gd or Nd affects its magnetic properties, showing potential for room-temperature ferromagnetism through electron or hole doping.

Contribution

It provides detailed insights into the magnetic coupling mechanisms in Gd- and Nd-doped ZnO and demonstrates how doping strategies can stabilize ferromagnetism at room temperature.

Findings

Gd doping leads to ferromagnetic coupling that can be enhanced by electron doping.

Nd doping results in ferromagnetism that can be improved by hole doping.

Native defects influence the ferromagnetic properties of doped ZnO.

Abstract

The electronic structure and magnetic coupling properties of rare-earth metals (Gd, Nd) doped ZnO have been investigated using first-principles methods. We show that the magnetic coupling between Gd or Nd ions in the nearest neighbor sites is ferromagnetic. The stability of the ferromagnetic coupling between Gd ions can be enhanced by appropriate electron doping into ZnO:Gd system and the room-temperature ferromagnetism can be achieved. However, for ZnO:Nd system, the ferromagnetism between Nd ions can be enhanced by appropriate holes doping into the sample. The room-temperature ferromagnetism can also be achieved in the \emph{n}-conducting ZnO:Nd sample. Our calculated results are in good agreement with the conclusions of the recent experiments. The effect of native defects (V$_{\rm{Zn}}$, V$_{\rm{O}}$) on the ferromagnetism is also discussed.