Current-Induced Crystallisation in Heusler Alloy Films

Half-metallic Heusler alloys have been investigated intensively in a view of spintronic device applications as an ideal spin source. However, a major obstacle for the applications is the requirement of high annealing temperature for their crystallisation. We have recently reported the reduction in the crystallisation temperature by promoting layer-by-layer growth on a (110) surface. In this study, we achieved current-induced crystallisation of a Co₂FeAl_0.5Si_0.5(110) Heusler alloy film by applying controlled current density, leading to the change in the corresponding resistivity. Due to the nature of a simple electrical current introduction, a nanoelectronics device does not require annealing processes but stores the operation cycle permanently, which minimises any atomic diffusion and interfacial mixing to degrade their performance. Hence, such current-induced crystallisation is expected to be used in a variety of nanoelectronics devices, including a neuromorphic node network, which can revolutionalise solid state memory.