Magnetoresistive detection of perpendicular switching in a magnetic insulator

TL;DR

This paper demonstrates a practical magnetoresistive method to electrically detect perpendicular magnetization reversal in an insulating ferrimagnet, enabling advances in insulating spintronic device applications.

Contribution

It introduces a novel magnetoresistive detection technique for insulating ferrimagnets using a simple resistance readout, overcoming previous challenges in electrical detection.

Findings

Magnetoresistance depends on temperature, composition, and spacer thickness.

Spin-dependent scattering at the interface causes the observed magnetoresistance.

The method enables electrical detection of magnetization reversal in insulating magnetic materials.

Abstract

Spintronics offers promising routes for efficient memory, logic, and computing technologies. The central challenge in spintronics is electrically manipulating and detecting magnetic states in devices. The electrical control of magnetization via spin-orbit torques is effective in both conducting and insulating magnetic layers. However, the electrical readout of magnetization in the latter is inherently difficult, limiting its use in practical applications. Here, we demonstrate magnetoresistive detection of perpendicular magnetization reversal in an electrically insulating ferrimagnet, terbium iron garnet (TbIG). To do so, we use TbIG|Cu|TbCo, where TbCo is a conducting ferrimagnet and serves as the reference layer, and Cu is a nonmagnetic spacer. Current injection through Cu|TbCo allows us to detect the magnetization reversal of TbIG with a simple resistance readout during an external magnetic field sweep. By examining the effect of measurement temperature, TbCo composition, and Cu thickness on the sign and amplitude of the magnetoresistance, we conclude that the spin-dependent electron scattering at the TbIG|Cu interface is the underlying cause. Technologically-feasible magnetoresistive detection of perpendicular switching in a ferrimagnetic garnet is a breakthrough, as it opens broad avenues for novel insulating spintronic devices and concepts.