Electric field effect in diluted magnetic insulator anatase Co: TiO 2

An external electric field induced reversible modulation of a room temperature magnetic moment and coercive field is achieved in an epitaxial and insulating thin film of dilutely cobalt-doped anatase TiO 2. This first demonstration of an electric field effect in any oxide-based diluted ferromagnet is realized in a high quality epitaxial heterostructure of PbZr 0.2Ti 0.8O 3/Co: TiO 2/SrRuO 3 grown on (001) LaAlO 3. The observed effect, which is about 15% in strength in a given heterostructure, can be modulated over several cycles. Possible mechanisms for electric field induced modulation of insulating ferromagnetism are discussed. © 2005 The American Physical Society.