Room Temperature Ferromagnetism of Ni-doped SnO2 System

Abstract

A series of Sn 1-x Ni x O 2 films were fabricated by sol-gel method. All samples have pure rutile structure and exhibit room temperature ferromagnetism (RTFM). Magnetic moment per Ni ion decreases with the increase of Ni doping because antiferromagnetic super-exchange interaction takes place in the nearest neighbour Ni 2+ ions for the samples with high x. The results of the annealing at oxidizing and reducing atmosphere show oxygen vacancies play a crucial role in producing ferromagnetism. This result supports that the origin of RTFM can be explained with Bound magnetic polaron (BMP) model.