Algebraic decay of the nonadiabaticity arising through chiral spin transfer torque in magnetic domain walls with Rashba spin-orbit interaction

TL;DR

This paper theoretically investigates how Rashba spin-orbit coupling causes a slow algebraic decay of nonadiabatic spin transfer torque in magnetic domain walls, with implications for spintronic device design.

Contribution

It reveals that Rashba spin-orbit interaction induces an algebraic decay of nonadiabaticity, contrasting with exponential decay in systems without such coupling.

Findings

Nonadiabaticity exhibits inverse power law decay with domain wall width.

Rashba spin-orbit coupling causes chiral spin transfer torque.

Decay is slower than in systems without Rashba interaction.

Abstract

Spin transfer torque in a two dimensional electron gas system without space inversion symmetry was theoretically investigated by solving the Pauli-Schr\"{o}dinger equation for the itinerant electrons inside magnetic domain walls. Due to the presence of the Rashba spin-orbit coupling induced by the broken inversion symmetry, the spin transfer torque is chiral and the nonadiabaticity, which is defined to measure the relative importance of the nonadiabatic, field-like torque to the adiabatic, damping-like torque, exhibits an inverse power law decay as the domain wall width is increased. This algebraic decay is much slower than the exponential decay observed for systems without the Rashba spin-orbit coupling, and may find applications in innovative design of spintronic devices utilising magnetic topological textures such as magnetic domain walls and skyrmions.