Heat-Treatment-Induced Switching of Magnetic States in the Doped Polar Semiconductor Ge$_{1-x}$Mn$_x$Te

TL;DR

This study demonstrates that heat-treatment can reversibly switch magnetic phases in Mn-doped GeTe, enabling magnetic phase-change memory with significant changes in ferromagnetic transition temperatures.

Contribution

It introduces heat-treatment as a method to control and switch between magnetic phases in a doped semiconductor, revealing a new approach for magnetic memory devices.

Findings

Heat-treatment alters magnetic phases in Ge$_{1-x}$Mn$_x$Te.

Maximum Curie temperature reaches approximately 180 K.

Reversible switching confirms magnetic phase-change memory potential.

Abstract

Cross-control of a material property - manipulation of a physical quantity (e.g., magnetisation) by a nonconjugate field (e.g., electrical field) - is a challenge in fundamental science and also important for technological device applications. It has been demonstrated that magnetic properties can be controlled by electrical and optical stimuli in various magnets. Here we find that heat-treatment allows the control over two competing magnetic phases in the Mn-doped polar semiconductor GeTe. The onset temperatures $T_{\rm c}$ of ferromagnetism vary at low Mn concentrations by a factor of five to six with a maximum $T_{\rm c} \approx 180$ K, depending on the selected phase. Analyses in terms of synchrotron x-ray diffraction and energy dispersive x-ray spectroscopy indicate a possible segregation of the Mn ions, which is responsible for the high-$T_{\rm c}$ phase. More importantly, we demonstrate that the two states can be switched back and forth repeatedly from either phase by changing the heat-treatment of a sample, thereby confirming magnetic phase-change- memory functionality.