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 degrees C. It is shown that the samples transform from anatase phase to rutile phase of TiO2 as the annealing temperature increases to 700 degrees 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.
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