Abstract

In order to investigate the effect of annealing conditions on the structural and magnetic properties, Vanadium-doped TiO₂ powders have been synthesized by a sol–gel technique in air and then postannealed in argon atmosphere at different temperatures from 500 to 850 C. It is shown that the samples transform from anatase phase to rutile phase of TiO₂ as the annealing temperature increases to 700 C. Meanwhile, room temperature ferromagnetism is enhanced after postannealing in argon atmosphere and the ferromagnetism increases with annealing temperatures. A plausible explanation for the enhancement of ferromagnetism with annealing temperatures is presented in terms of bound magnetic polaron model.

Keywords: A. Diluted magnetic semiconductors; D. Room temperature ferromagnetism