Ferromagnetism at 300 K in spin-coated anatasea and rutile Ti0.95Fe0.05O2 films

TL;DR

This study demonstrates that spin-coated Ti0.95Fe0.05O2 thin films in anatase and rutile phases exhibit ferromagnetism at 300 K after vacuum annealing, with Curie temperatures above 350 K, indicating potential for room-temperature magnetic applications.

Contribution

First demonstration of room-temperature ferromagnetism in spin-coated anatase and rutile Ti0.95Fe0.05O2 films prepared via metal organic precursors.

Findings

Vacuum annealing significantly enhances magnetic moments.

Ferromagnetic Curie temperature exceeds 350 K.

Films remain transparent in the visible spectrum.

Abstract

Thin films of Ti1-xFexO2 (x=0 and 0.05) have been prepared on sapphire substrates by spin-on technique starting from metal organic precursors. When heat treated in air at 550 and 700 degrees C respectively, these films present pure anatase and rutile structures as shown both by X-ray diffraction and Raman spectroscopy. Optical absorption indicate a high degree of transparency in the visible region. Such films show a very small magnetic moment at 300 K. However, when the anatase and the rutile films are annealed in a vacuum of 1x10-5 Torr at 500 degrees C and 600 degrees C respectively, the magnetic moment, at 300 K, is strongly enhanced reaching 0.46 $\mu$B/Fe for the anatase sample and 0.48 $\mu$B/Fe for the rutile one. The ferromagnetic Curie temperature of these samples is above 350 K.