External control of the direction of magnetization in ferromagnetic InMnAs/GaSb heterostructures

TL;DR

This study demonstrates external control over magnetization direction in ferromagnetic InMnAs/GaSb heterostructures, showing temperature-dependent axis rotation and light-induced reorientation via a bolometric effect, supported by experimental and theoretical analysis.

Contribution

It introduces a method to control magnetization direction externally in ferromagnetic heterostructures, including light-induced reorientation, with supporting theoretical modeling.

Findings

Magnetization direction can be controlled by temperature.

Light can induce reorientation of magnetization axis.

Theoretical model reproduces magnetization reorientation tendencies.

Abstract

In this paper, we demonstrate external control over the magnetization direction in ferromagnetic (FM) In_{1-x}Mn_{x}As/GaSb heterostructures. FM ordering with T_C as high as 50 K is confirmed by SQUID magnetization, anomalous Hall effect (AHE), and magneto-optical Kerr effect (MOKE) measurements. Even though tensile strain is known to favor an easy axis normal to the layer plane, at low temperatures we observe that the magnetization direction in several samples is intermediate between the normal and in-plane axes. As the temperature increases, however, the easy axis rotates to the direction normal to the plane. We further demonstrate that the easy magnetization axis can be controlled by incident light through a bolometric effect, which induces a pronounced increase in the amplitude of the AHE. A mean-field-theory model for the carrier-mediated ferromagnetism reproduces the tendency for dramatic reorientations of the magnetization axis, but not the specific sensitivity to small temperature variations.