Ferromagnetism in SnO₂ by Mechanical Milling

Abstract

Room temperature ferromagnetism was observed in the rutile-type SnO 2 by mechanical milling (MM). XRD results showed that the particle diameter d of SnO 2 powder was 22-32 nm after MM. Magnetization measurement showed that saturated magnetization M s at 300K was 7.8×10 Except for the TM-doped SnO 2 , the room temperature ferromagnetism, induced by the oxygen vacancies, has been reported for SnO 2 thin films, nano-particles and nano-wires [5][6][7][8]. As for the SnO 2 nano-particles [6], the sample preparations were performed by chemical reaction between organic solvent and metal nitrate. However the observed magnetization was nearly paramagnetic with very small hysteresis in Ref. 6. In the present study, SnO 2 nano-particles were prepared by the mechanical milling (MM) method using planetary ball mill, and the production of vacancy was expected on the surface of SnO 2 nano-particle. The observation of clear magnetic hysteresis at room temperature is reported for the present system.