Room temperature ferromagnetism and magnetoresistance in chromium-doped indium tin oxide

The possibility of room-temperature ferromagnetism in In₂O₃ thin films with bixbyite structure by Sn and Cr atom co-doping is investigated. For an n-type Cr 5 mol% film, room-temperature ferromagnetism is observed with a saturated magnetization ∼0.7 emu/cm³, remnant magnetization ∼0.2 emu/cm³, cohesive field of 28 Oe. Also, the M-T curves in magnetic field of 1 kOe for zero field cooling and field cooling for Cr 5 mol% film display the steep increase of magnetization below 30 K for decreasing temperature without abnormality as Neel temperature of antiferromagnetism and noticeable deviation indicating spin-glass behavior are present. A positive magnetoresistance is observed in the region from 5 kOe to 28 kOe for the Cr 5 mol% film. This considers the s-d exchange coupling between the conducting carrier and localized spins of Cr ions.