Ferrimagnetic Heusler tunnel junctions with fast spin-transfer torque switching enabled by low magnetization

TL;DR

This paper demonstrates that ferrimagnetic Heusler alloy Mn3Ge enables fast, reliable, and low-current switching in magnetic tunnel junctions, significantly advancing high-performance, scalable magnetic random access memory technology.

Contribution

It introduces the use of low magnetization ferrimagnetic Heusler alloy Mn3Ge for magnetic tunnel junctions, achieving high TMR and fast switching on amorphous substrates.

Findings

High tunneling magnetoresistance at ambient temperature

Fast and reliable switching with low magnetization material

Compatible with amorphous substrates for scalable fabrication

Abstract

Magnetic random access memory that uses magnetic tunnel junction memory cells is a high performance, non-volatile memory technology that goes beyond traditional charge-based memories. Today its speed is limited by the high magnetization of the memory storage layer. Here we show that fast and highly reliable switching is possible using a very low magnetization ferrimagnetic Heusler alloy, Mn3Ge. Moreover, the tunneling magnetoresistance is the highest yet achieved for a ferrimagnetic material at ambient temperature. Furthermore, the devices were prepared on technologically relevant amorphous substrates using a novel combination of a nitride seed layer and a chemical templating layer. These results show a clear path to the lowering of switching currents using ferrimagnetic Heusler materials and, therefore, to the scaling of high performance magnetic random access memories beyond those nodes possible with ferromagnetic devices.