Rutile-type oxide-diluted magnetic semiconductor: Mn-doped SnO2

Epitaxial films of an oxide-diluted magnetic semiconductor with rutile structure, Mn-doped ${\mathrm{SnO}}_2,$ have been fabricated by pulsed-laser deposition. As the Mn content increases, systematic changes in lattice constants and in-gap absorption are observed. Magnetization measurements show almost paramagnetic behavior. The injection of $n$ -type carrier over ${10}^{20} {\mathrm{cm}}^{\text{−3}}$ is achieved by Sb doping. A ${\mathrm{Sn}}_{\text{0.95}}{\mathrm{Mn}}_{\text{0.05}}{\mathrm{O}}_2:\mathrm{Sb}$ film shows giant positive magnetoresistance as large as 60% at 5 K.