Room temperature ferromagnetism in Mn- and Fe-doped indium tin oxide thin films

Abstract

Undoped and transition-metal doped indium tin oxide films have been grown by pulsed laser deposition technique, on single crystalline c -plane (0001) and r -plane (1102) sapphire substrates maintained at 500-850 °C. Magnetization measurements of films deposited at different temperatures indicate that ferromagnetism appears for deposition temperatures, Tdep >600 °C, with the highest moment for films deposited around 750 °C. Qualitative different ferromagnetic behavior has been observed at room temperature in Fe- and Mn-doped thin films. The stable, hysteretic ferromagnetism of the Fe-doped films is due to the presence of magnetite, as seen in transmission Mössbauer spectra. The Mn-doped films show anhysteretic ferromagnetism which decays over time. It is somehow intrinsic, but not due to the Mn ions, which remains paramagnetic down to 4 K. No anomalous Hall effect is observed. © 2008 American Institute of Physics.