Origin of Ferromagnetism in nitrogen embedded ZnO:N thin films

TL;DR

This paper investigates the origin of ferromagnetism in nitrogen-embedded ZnO thin films, proposing a defect-related mechanism involving electron compensation and bound magnetic polarons that explains the observed magnetic properties.

Contribution

It introduces a novel defect-based mechanism for ferromagnetism in ZnO:N films, supported by experimental evidence and a bound magnetic polaron model.

Findings

Nitrogen ions act as defects in ZnO:N films.

Electrons in Zn d-orbitals compensate nitrogen dangling bonds.

Ferromagnetism is explained by bound magnetic polarons.

Abstract

Nitrogen embedded ZnO:N films prepared by pulsed laser deposition exhibit significant ferromagnetism. The nitrogen ions contained in ZnO confirmed by Secondary Ion Microscopic Spectrum and Raman experiments and the embedded nitrogen ions can be regarded as defects. According to the experiment results, a mechanism is proposed based on one of the electrons in the completely filled d-orbits of Zn that compensates the dangling bonds of nitrogen ions and leads to a net spin of one half in the Zn orbits. These one half spins strongly correlate with localized electrons that are captured by defects to form ferromagnetism. Eventually, the magnetism of nitrogen embedded ZnO:N films could be described by a bound magnetic polaron model.