Electric Field Effect in Diluted Magnetic Insulator AnataseCo:TiO2

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 $\mathrm{Ti}{\mathrm{O}}_2$. This first demonstration of an electric field effect in any oxide-based diluted ferromagnet is realized in a high quality epitaxial heterostructure of $\mathrm{PbZ}{\mathrm{r}}_{0.2}\mathrm{T}{\mathrm{i}}_{0.8}{\mathrm{O}}_3/\mathrm{Co}\mathrm{\text{:}}\mathrm{Ti}{\mathrm{O}}_2/\mathrm{SrRu}{\mathrm{O}}_3$ grown on (001) $\mathrm{LaAl}{\mathrm{O}}_3$. 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.