Ferromagnetism modulation by phase change in Mn-doped GeTe chalcogenide magnetic materials

Abstract

In this work, an effective method to modulate the ferromagnetic properties of Mn-doped GeTe chalcogenide-based phase change materials is presented. The microstructure of the phase change magnetic material Ge1−x Mn x Te thin films was studied. The X-ray diffraction results demonstrate that the as-deposited films are amorphous, and the crystalline films are formed after annealing at 350 °C for 10 min. Crystallographic structure investigation shows the existence of some secondary magnetic phases. The lattice parameters of Ge1−x Mn x Te (x = 0.04, 0.12 and 0.15) thin films are found to be slightly different with changes of Mn compositions. The structural analysis clearly indicates that all the films have a stable rhombohedral face-centered cubic polycrystalline structure. The magnetic properties of the amorphous and crystalline Ge0.96Mn0.04Te were investigated. The measurements of magnetization (M) as a function of the magnetic field (H) show that both amorphous and crystalline phases of Ge0.96Mn0.04Te thin film are ferromagnetic and there is drastic variation between amorphous and crystalline states. The temperature (T) dependence of magnetizations at zero field cooling (ZFC) and field cooling (FC) conditions of the crystalline Ge0.96Mn0.04Te thin film under different applied magnetic fields were performed. The measured data at 100 and 300 Oe applied magnetic fields show large bifurcations in the ZFC and FC curves while on the 5,000 Oe magnetic field there is no deviation.