Takashi Umemoto

Physical properties of CoFe/IrMn spin-valves prepared using ion beam sputtering with an Xe-H2 mixture gas

Co90Fe10/Cu/Co90Fe10/Ir25Mn75 spin-valves with a Ta seed layer were prepared by ion beam sputtering. Improvements in magnetoresistive (MR) and magnetic properties were obtained by adding H2 to Xe sputtering gas. Specifically, the coercivity in the free Co90Fe10 layer considerably decreased as the H2 flow rate was increased. Furthermore, exchange coupling between the Ir25Mn75 and pinned Co90Fe10 layers became stronger in the preparation under the higher H2 flow rate. X-ray diffraction, transmission electron microscopy, and secondary ion mass spectroscopy observations suggest that micro-crystallization of each layer is responsible for improving the MR and magnetic properties.