Program Highlights

Inducing Magnetism by Proximity

Christian Binek and Peter Dowben
Nebraska MRSEC

Unlike ferromagnets, paramagnetic materials do not possess a spontaneous magnetic polarization. The polarization can be induced, however, by proximity of a magnetic material which has a non-vanishing magnetization on its surface. Nebraska MRSEC researchers have demonstrated that paramagnetic materials, such as platinum and palladium, reveal magnetism when thin films of these materials are deposited on a magnetoelectric chromia. Chromia does not possess bulk magnetization, but it has a robust magnetization on its surface – a distinctive property of the magnetoelectric material. The surface magnetization of chromia induces magnetism in the paramagnetic overlayers, which was detected by the researchers. They observed changes in the polarization of a laser light when it was reflected from the paramagnetic films, indicating the presence of the induced magnetization. This finding opens the door to use paramagnetic overlayers for the detection of the surface magnetization of chromia, which plays a key role in prospective ultra-low power memory and logic devices.

This research is supported by the National Science Foundation, Division of Materials Research, Materials Research Science and Engineering Program, Grant DMR-1420645.

Detection of induced magnetization in paramagnetic thin film of platinum (Pt) deposited on a surface of chromia (Cr₂O₃). The polarization of electric field (E) rotates when the linearly polarized light is reflected from the magnetized paramagnetic film.