Effect of Crystallinity on Magnetic Properties in Manganese-Doped Indium Tin Oxide Films

Mn-doped indium tin oxide (ITO) films were deposited on single crystalline yttria stabilized zirconia (YSZ) substrates with (111) plane orientation and alkali-free glass substrates by rf magnetron sputtering. The epitaxial relationships between the Mn-doped ITO films and YSZ(111) substrates was confirmed by X-ray diffraction measurements. According to the X-ray rocking curve, the epitaxial Mn-doped ITO film on YSZ(111) substrate indicated the high degree of the crystalline alignment. The epitaxial and polycrystalline Mn-doped ITO films exhibited low resistivity and high transparency. Room-temperature ferromagnetism was observed in both the epitaxial and polycrystalline Mn-doped ITO films. The Curie temperature of these films was estimated to be higher than 400 K. The crystallinity difference between the epitaxial and polycrystalline films has little influence on the magnetic properties of the Mn-doped ITO films. The origin of the room-temperature ferromagnetism was discussed on the basis of the correlation between the magnetization and carrier concentration of the Mn-doped ITO films.