SnO 2 doped with Mn, Fe or Co: Room temperature dilute magnetic semiconductors

Room temperature ferromagnetism is found in (Sn1−xMx)O2 (M=Mn, Fe, Co, x=0.05) ceramics where x-ray diffraction confirms the formation of a rutile-structure phase. Room temperature saturation magnetization of 0.2 and 1.8 Am2 kg−1 for (Sn0.95Mn0.05)O2 and (Sn0.95Fe0.05)O2, respectively, corresponds to a moment of 0.11 or 0.95 μB per Mn or Fe atom. The Curie temperatures are 340 and 360 K, respectively. The magnetization cannot be attributed to any identified impurity phase. Fe57 Mössbauer spectra of the Fe-doped SnO2 samples, recorded at room temperature and 16 K, show that about 85% of the iron is in a magnetically ordered high spin Fe3+ state, the remainder being paramagnetic.