Magnetocrystalline anisotropy controlled local magnetic configurations in (Ga,Mn)As spin-transfer-torque microdevices

TL;DR

This paper demonstrates how locally tunable magnetocrystalline anisotropy in (Ga,Mn)As microdevices can control magnetic configurations and enable current-induced switching at low current densities, advancing spintronic device design.

Contribution

It introduces a method to control magnetic states via lattice-relaxation-induced anisotropy in dilute ferromagnets, with experimental and theoretical validation.

Findings

Magnetocrystalline anisotropy can replace dipolar fields in magnetic configuration control.

Current-induced in-plane magnetization switching occurs below the Curie temperature.

Switching is achieved at low current densities (~10^5 A/cm^2) with domain-wall spin-transfer effects.

Abstract

The large saturation magnetization in conventional dense moment ferromagnets offers flexible means of manipulating the ordered state through demagnetizing shape anisotropy fields but these dipolar fields, in turn, limit the integrability of magnetic elements in information storage devices. We show that in a (Ga,Mn)As dilute moment ferromagnet, with comparatively weaker magnetic dipole interactions, locally tunable magnetocrystalline anisotropy can take the role of the internal field which determines the magnetic configuration. Experiments and theoretical modeling are presented for lithographically patterned microchannels and the phenomenon is attributed to lattice relaxations across the channels. The utility of locally controlled magnetic anisotropies is demonstrated in current induced switching experiments. We report structure sensitive, current induced in-plane magnetization switchings well below the Curie temperature at critical current densities 10^5 Acm^-2. The observed phenomenology shows signatures of a contribution from domain-wall spin-transfer-torque effects.