Spin-flop driven interfacial tunneling magnetoresistance in an antiferromagnetic tunnel junction

TL;DR

This paper demonstrates a 2D antiferromagnetic tunnel junction exhibiting tunable interfacial tunneling magnetoresistance driven by surface spin-flop effects, highlighting potential for advanced spintronic applications.

Contribution

It introduces a full van der Waals magnetic tunnel junction using 2D antiferromagnetic FeCoGeTe2 electrodes with tunable TMR influenced by surface spin-flop effects.

Findings

TMR reaches about 25% at 100 K with low current.

TMR can be tuned in amplitude and sign by bias and temperature.

Surface spin-flop effect enables flexible memory states.

Abstract

The utilization of two-dimensional (2D) materials in magnetic tunnel junctions (MTJs) has shown excellent performance and rich physics. As for 2D antiferromagnets, the magnetic moments in different layers respond asynchronously and can be configured at various states under different magnetic fields, showing the possibility of efficient magnetic and electrical tunability. In this report, A-type antiferromagnetic (AFM) material (Fe0.5Co0.5)5GeTe2 (FCGT) works as electrodes to realize full van der Waals magnetic tunnel junctions. Owing to the interfacial effect, the even-layer FCGT, although with zero net magnetization, exhibits spin selectivity in MTJ architecture contributing to a tunneling magnetoresistance (TMR) reaching about 25% at a low operating current 1 nA at 100 K and persists near room temperature. Due to the surface spin-flop (SSF) effect in antiferromagnetic FCGT, the alternation flexibility between the volatile and nonvolatile memory behavior is achieved. The interfacial TMR can be tuned efficiently in amplitude and even sign under different bias currents and temperatures. These findings show precise magnetoelectric manipulation in MTJs based on 2D antiferromagnets and highlight the promise of 2D antiferromagnets for spintronic devices.