Structure and magnetic properties of Sn_(1-x)Mn_xO_2

摘要

The microstructure and magnetic properties have been investigated systematically for Sn_(1-x)Mn_xO_2 polycrystalline powder samples with x=0.02-0.08 synthesized by a solid-state reaction method. X-ray diffraction revealed that all samples are pure rutile-type tetragonal phase and the cell parameters a and c decrease monotonously with the increase in Mn content, which indicated that Mn ions substitute into the lattice of SnO_2. Magnetic measurements revealed that all samples exhibit room temperature ferromagnetism. Furthermore, magnetic investigations demonstrate that magnetic properties strongly depend on doping content, x. The average magnetic moment per Mn atom decreases with increase in the Mn content, because antiferromagnetic super-exchange interaction takes place within the neighbor Mn~(3+) ions through O~(2-) ions for the samples with higher Mn doping. Our results indicate that the ferromagnetic property is intrinsic to the SnO_2 system and is not a result of any secondary magnetic phase or cluster formation.