Tracking defect-induced ferromagnetism in GaN:Gd

TL;DR

This study investigates the magnetic properties of Gd-doped GaN layers, revealing defect-related ferromagnetism influenced by oxygen co-doping, with implications for understanding magnetic interactions in semiconductor materials.

Contribution

It demonstrates the role of defects and oxygen co-doping in mediating ferromagnetism in GaN:Gd, providing new insights into defect-induced magnetic phenomena.

Findings

Defects at ~10^19 cm^-3 influence magnetic properties.

Positron annihilation spectroscopy does not link Ga vacancies to ferromagnetism.

Oxygen co-doping enhances room-temperature ferromagnetism.

Abstract

We report on the magnetic properties of GaN:Gd layers grown by molecular beam epitaxy (MBE). A poor reproducibility with respect to the magnetic properties is found in these samples. Our results show strong indications that defects with a concentration of the order of 10^19 cm^-3 might play an important role for the magnetic properties. Positron annihilation spectroscopy does not support the suggested connection between the ferromagnetism and the Ga vacancy in GaN:Gd. Oxygen co-doping of GaN:Gd promotes ferromagnetism at room temperature and points to a role of oxygen for mediating ferromagnetic interactions in Gd doped GaN.