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

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 superconducting quantum interference device magnetization, anomalous Hall effect (AHE), and magneto-optical Kerr effect 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 in 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.