Bulk Sn1-xMnxO2 magnetic semiconductors without room-temperature ferromagnetism

Polycrystalline Sn1-xMnxO2 (0 <= x <= 0.05) diluted magnetic semiconductors were prepared by solid-state reaction method and their structural and magnetic properties had been investigated systematically. The three Mn-doped samples (x = 0.01, 0.03, 0.05) undergo paramagnetic to ferrornagnetic phase transitions upon cooling, but their Curie temperatures are far lower than room temperature. The magnetization cannot be attributed to any identified impurity phase. It is also found that the magnetization increases with increasing Mn doping, while the ratio of the Mn ions contributing to ferrornagnetic ordering to the total Mn ions decreases. (c) 2006 Elsevier Ltd. All rights reserved.