Microstructure and magneto-transport properties of CPP-GMR pseudo spin-valves with polycrystalline Heusler alloy Co_2Mn(Ga_(0.25)Ge_(0.75))

摘要

A large resistance-area product change, △RA, of at least several mΩ·μm~2 of current-perpendicular-to-plane giant magneto-resistance (CPP-GMR) is required for achieving ultrahigh recording density in hard disk drives. For the fabrication of practical read sensors, polycrystalline thin film is needed due to the requirements in the current read sensor manufacturing process. Additionally, low annealing temperature is preferred so as to avoid inter-diffusion in film layers such as IrMn. Thus, achieving a high spin polarization using a poly-crystalline Heusler alloy under a low annealing temperature is important. In this work, CPP-GMR pseudo spin-valves (PSVs) using polycrystalline Co_2Mn(Co_2Mn(Ga_(0.25)Ge_(0.75)) (CMGG) Heusler alloy was studied.