High-temperature ferromagnetism in manganese-doped indium–tin oxide films

High-temperature ferromagnetism is demonstrated in Mn-doped indium–tin oxide (ITO) films deposited using reactive thermal evaporation. These films were grown on sapphire (0001), $\mathrm{Si}∕\mathrm{Si}{\mathrm{O}}_2$ as well as Si (100) substrates with the highest magnetic moment observed around $0.8{\mu }_B∕\mathrm{Mn}$ in 5% Mn-doped ITO films. The electrical conduction is $n$ type and the carrier concentration is $\sim 2.5\times {10}^{19}{\mathrm{cm}}^{-3}$ for 5% Mn doping. An anomalous Hall effect is observed in magnetotransport measurements, showing that the charge carriers are spin polarized, revealing the magnetic interaction between itinerant electrons and localized Mn spins. The carrier concentration can be varied independent of the Mn concentration in this transparent ferromagnetic semiconductor for its easy integration into magneto-optoelectronic devices.