Mechanism-based Tuning of Room-temperature Ferromagnetism in Mn-doped \b{eta}-Ga2O3 by Annealing Atmospher

TL;DR

This study demonstrates how annealing atmosphere modulates room-temperature ferromagnetism in Mn-doped eta-Ga2O3 films, revealing oxygen vacancies as key to controlling magnetic properties for spintronic applications.

Contribution

It introduces a mechanism-based approach to tune ferromagnetism in Mn-doped eta-Ga2O3 via annealing atmosphere, highlighting oxygen vacancies' role in magnetic behavior.

Findings

GMO-air exhibits 170% higher saturation magnetization than GMO-O2.

Oxygen vacancies control ferromagnetism through bound magnetic polarons.

Annealing atmosphere influences vacancy defect concentrations and magnetic properties.

Abstract

Mn-doped \b{eta}-Ga2O3 (GMO) films with room-temperature ferromagnetism (RTFM) are synthesized by polymer-assisted deposition and the effects of annealing atmosphere (air or pure O2 gas) on their structures and physical properties are investigated. The characterizations show that the concentrations of vacancy defects and Mn dopants in various valence states and lattice constants of the samples are all modulated by the annealing atmosphere. Notably, the samples annealed in air (GMO-air) exhibit a saturation magnetization as strong as 170% times that of the samples annealed in pure O2 gas (GMO-O2), which can be quantitatively explained by oxygen vacancy (VO) controlled ferromagnetism due to bound magnetic polarons established between delocalized hydrogenic electrons of VOs and local magnetic moments of Mn2+, Mn3+, and Mn4+ ions in the samples. Our results provide insights into mechanism-based tuning of RTFM in Ga2O3 and may be useful for design, fabrication, and application of related spintronic materials.