Hole mediated ferromagnetism in Cu-doped ZnO thin films

TL;DR

This paper demonstrates that hole doping via arsenic diffusion in Cu-doped ZnO thin films induces room temperature ferromagnetism, with enhanced magnetic interactions confirmed by spectroscopic and magnetic measurements.

Contribution

It introduces a novel method of hole doping in ZnO:Cu films through As diffusion from substrates, leading to room temperature ferromagnetism.

Findings

Hole doping confirmed by As K-edge spectra.

Enhanced ferromagnetism after hole doping.

Spectroscopic evidence of increased magnetic interactions.

Abstract

We report the successful synthesis of ZnO:Cu thin films doped with holes, resulting in room temperature ferromagnetism. Hole doping is achieved by As-diffusion from the GaAs substrate into ZnO films, assisted by thermal annealing. The As-diffusion is probed with the help of x-ray absorption spectra collected at the As K-edge which show enhanced signature of diffusion in the annealed samples. Introduction of holes, due to the As doping, in ZnO films is further evidenced by the Cu L3,2-edge spectra. XMCD and magnetic measurements show that the ferromagnetic interaction between doped Cu ions is enhanced after hole doping.