Engineering spin-orbit torque in Co/Pt multilayers with perpendicular magnetic anisotropy

TL;DR

This paper explores how inserting Ta or Cu layers in Co/Pt multilayers enhances spin-orbit torque efficiency and thermal stability, crucial for advancing spintronic device performance.

Contribution

It demonstrates that layer insertion modifies spin-orbit torque without losing perpendicular magnetic anisotropy, and increasing layer number boosts efficiency and stability.

Findings

Spin-orbit torque efficiency is significantly increased by inserting Ta or Cu layers.

Layer number correlates positively with torque efficiency and thermal stability.

Perpendicular magnetic anisotropy is maintained despite modifications.

Abstract

To address thermal stability issues for spintronic devices with a reduced size, we investigate spin-orbit torque in Co/Pt multilayers with strong perpendicular magnetic anisotropy. Note that the spin-orbit torque arises from the global imbalance of the spin currents from the top and bottom interfaces for each Co layer. By inserting Ta or Cu layers to strengthen the top-down asymmetry, the spin-orbit torque efficiency can be greatly modified without compromised perpendicular magnetic anisotropy. Above all, the efficiency builds up as the number of layers increases, realizing robust thermal stability and high spin-orbit-torque efficiency simultaneously in the multilayers structure.