Shape anisotropy revisited in single-digit nanometer magnetic tunnel junctions

TL;DR

This paper demonstrates that shape anisotropy can enable stable, current-driven magnetization switching in magnetic tunnel junctions smaller than 10 nm, advancing nano-magnetics and spintronics.

Contribution

It revisits shape anisotropy in perpendicular magnetic tunnel junctions, enabling stable switching at sub-10 nm scales without new materials.

Findings

Successful current-driven switching in <10 nm junctions

Shape anisotropy provides thermal stability at ultrafine scales

Advances the development of single-digit-nanometer spintronic devices

Abstract

Nanoscale magnetic tunnel junction plays a pivotal role in magnetoresistive random access memories. Successful implementation depends on a simultaneous achievement of low switching current for the magnetization switching by spin-transfer torque and high thermal stability, along with a continuous reduction of junction size. Perpendicular-easy-axis CoFeB/MgO stacks possessing interfacial anisotropy have paved the way down to 20-nm scale, below which a new approach needs to be explored. Here we show magnetic tunnel junctions that satisfy the requirements at ultrafine scale by revisiting shape anisotropy, which is a classical part of magnetic anisotropy but has not been fully utilized in the current perpendicular systems. Magnetization switching solely driven by current is achieved for junctions smaller than 10 nm where sufficient thermal stability is provided by shape anisotropy without adopting new material systems. This work is expected to push forward the development of magnetic tunnel junctions towards single-digit-nm-scale nano-magnetics/spintronics.