Field-Free Switching of Perpendicular Magnetization in an Ultrathin Epitaxial Magnetic Insulator.

Husain, Sajid; Prestes, Nicholas F; Fayet, Olivier; Collin, Sophie; Godel, Florian; Jacquet, Eric; Denneulin, Thibaud; Dunin-Borkowski, Rafal E et al. · Nano Lett · 2024

basic_science · Level V

Where this comes from

Abstract

For energy-efficient magnetic memories, switching of perpendicular magnetization by spin-orbit torque (SOT) appears to be a promising solution. This SOT switching requires the assistance of an in-plane magnetic field to break the symmetry. Here, we demonstrate the field-free SOT switching of a perpendicularly magnetized thulium iron garnet (Tm<sub>3</sub>Fe<sub>5</sub>O<sub>12</sub>, TmIG). The polarity of the switching loops, clockwise or counterclockwise, is determined by the direction of the initial current pulses, in contrast with field-assisted switching where the polarity is controlled by the direction of the magnetic field. From Brillouin light scattering, we determined the Dzyaloshinskii-Moriya interaction (DMI) induced by the Pt-TmIG interface. We will discuss the possible origins of field-free switching and the roles of the interfacial DMI and cubic magnetic anisotropy of TmIG. This discussion is substantiated by magnetotransport, Kerr microscopy, and micromagnetic simulations. Our observation of field-free electrical switching of a magnetic insulator is an important milestone for low-power spintronic devices.