Temperature dependence of interlayer coupling in perpendicular magnetic tunnel junctions with GdOx barriers

TL;DR

This study investigates how temperature affects interlayer magnetic coupling in GdOx-based perpendicular magnetic tunnel junctions, revealing unusual temperature-dependent behavior and potential magnetic contributions from Gd ions.

Contribution

It provides the first detailed analysis of temperature effects on GdOx barrier quality and interlayer coupling mechanisms in magnetic tunnel junctions.

Findings

Barrier quality comparable to AlOx and MgO with low spin-independent conductance

Strong temperature dependence of interlayer coupling including sign changes below 80 K

Unexplained behavior not accounted for by existing models, possibly due to Gd ion magnetic moments

Abstract

Perpendicular magnetic tunnel junctions with GdOX tunneling barriers have shown a unique voltage controllable interlayer magnetic coupling effect. Here we investigate the quality of the GdOX barrier and the coupling mechanism in these junctions by examining the temperature dependence of the tunneling magnetoresistance and the interlayer coupling from room temperature down to 11 K. The barrier is shown to be of good quality with the spin independent conductance only contributing a small portion, 14%, to the total room temperature conductance, similar to AlOX and MgO barriers. The interlayer coupling, however, shows an anomalously strong temperature dependence including sign changes below 80 K. This non-trivial temperature dependence is not described by previous models of interlayer coupling and may be due to the large induced magnetic moment of the Gd ions in the barrier.