Light Control of Ferromagnetism in ZnO Films on Pt Substrate at Room Temperature

Abstract

The control of ferromagnetism by light at room temperature is essential for the development of some optical-magnetic coupling devices, data storage and quantum computation techniques. In the present work, we demonstrate that the ferromagnetism of a semiconducting ZnO film on Pt substrate can be controlled by nonpolarized ultraviolet or violet light. The illumination of light with sufficiently high frequency photons could excite photogenerated electron-hole pairs in the semiconducting ZnO film. The amount of oxygen vacancies in the ZnO film and the appearance of built-in electric field due to the heterostructured ZnO/Pt may play important roles in the light-induced changes in the ferromagnetism of the ZnO film.