Motors based on photo-magnetic materials

Abstract

Absorption of light by a substance does not change its magnetic properties. However, if redox reactions occur on the surface of a material when irradiated with light and a current loop is formed, it turns into a magnet. This study reports a method for producing a new type of material—photo-magnets, which are capable of changing their magnetic properties when exposed to light. The simplest photo-magnet is a bimetallic plate made of two dissimilar metals, one part of which is coated with a semiconductor material—zinc oxide—and it is immersed in a solution of hydrogen peroxide. When exposed to light, holes and electrons are formed in the semiconductor, which take part in redox reactions during the decomposition of hydrogen peroxide. Since a current loop is formed in this case, the photo-magnet becomes a source of a magnetic field. In addition, any loop with current in a non-uniform magnetic field is affected by a force whose nature is determined by the action of the Lorentz force on moving charges. Therefore, on the basis of photo-magnets, it is possible to create motors that will move in a non-uniform magnetic field when irradiated with light.