Compensation-dependent in-plane magnetization reversal processes in Ga1-xMnxP1-ySy

TL;DR

This study investigates how sulfur alloying affects in-plane magnetic anisotropy and reversal processes in Ga1-xMnxP, revealing that increased sulfur concentration modifies magnetic properties and induces double hysteresis loops.

Contribution

It demonstrates the impact of sulfur doping on magnetic anisotropy and reversal mechanisms in Ga1-xMnxP, combining experimental and modeling approaches.

Findings

Sulfur increases uniaxial magnetic anisotropy.

Double hysteresis loops develop with higher sulfur levels.

Magnetic property changes are linked to hole concentration reduction.

Abstract

We report the effect of dilute alloying of the anion sublattice with S on the in-plane uniaxial magnetic anisotropy and magnetization reversal process in Ga1-xMnxP as measured by both ferromagnetic resonance (FMR) and superconducting quantum interference device (SQUID) magnetometry. At T=5K, raising the S concentration increases the uniaxial magnetic anisotropy between in-plane <011> directions while decreasing the magnitude of the (negative) cubic anisotropy field. Simulation of the SQUID magnetometry indicates that the energy required for the nucleation and growth of domain walls decreases with increasing y. These combined effects have a marked influence on the shape of the field-dependent magnetization curves; while the direction remains the easy axis in the plane of the film, the field dependence of the magnetization develops double hysteresis loops in the [011] direction as the S concentration increases similar to those observed for perpendicular magnetization reversal in lightly doped Ga1-xMnxAs. The incidence of double hysteresis loops is explained with a simple model whereby magnetization reversal occurs by a combination of coherent spin rotation and noncoherent spin switching, which is consistent with both FMR and magnetometry experiments. The evolution of magnetic properties with S concentration is attributed to compensation of Mn acceptors by S donors, which results in a lowering of the concentration of holes that mediate ferromagnetism.