Ferromagnetism in Fe-doped SnO2 thin films

TL;DR

This study demonstrates that Fe-doped SnO2 thin films exhibit high-temperature ferromagnetism with inhomogeneous magnetic ordering, likely due to electron-mediated coupling via oxygen vacancies, offering potential for transparent magnetic materials.

Contribution

It reveals high-temperature ferromagnetism in Fe-doped SnO2 thin films and proposes a mechanism involving oxygen vacancies for magnetic coupling.

Findings

Curie temperature of 610 K

Spontaneous magnetization of 2.2 Am2kg-1

Only 23% of iron atoms are magnetically ordered

Abstract

Thin films grown by pulsed-laser deposition from targets of Sn0.95Fe0.05O2 are transparent ferromagnets with Curie temperature and spontaneous magnetization of 610 K and 2.2 Am2kg-1, respectively. The 57Fe Mossbauer spectra show the iron is all high-spin Fe3+ but the films are magnetically inhomogeneous on an atomic scale, with only 23 % of the iron ordering magnetically. The net ferromagnetic moment per ordered iron ion, 1.8 Bohr magnetons, is greater than for any simple iron oxide. Ferromagnetic coupling of ferric ions via an electron trapped in a bridging oxygen vacancy (F center) is proposed to explain the high Curie temperature