(001)-textured poly crystalline current-perpendicular-to-plane pseudo spin-valves using full Heusler alloy Co_2Fe(Ga_(0.5)Ge_(0.5))

摘要

Current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) devices using a Co-based full Heusler alloy hold great potential to be utilized as the read sensors in ultrahigh density hard disk drives due to their intrinsically low resistance-area product (RA) (tens of mΩμm~2) and the relatively high magnetoresistance of several tens percent. Recent investigations have shown that fully epitaxial pseudo spin valves (PSVs) with L2_1 or B2 ordered Co-based Heusler alloys prepared on MgO (001) single-crystalline substrates exhibit MR ratio of more than 50% and the resistance-change area product (ARA) exceeding 12 mΩμm~2 at room temperature. However, considering the industrial applicability, the CPP-GMR devices have to be developed on amorphous thermally oxidized Si substrates with polycrystalline film stack. In this work, we studied the (001)-textured polycrystalline CPP-GMR PSVs using full Heusler alloy Co_2Fe(Ga_(0.5)Ge_(0.5)) (CFGG) and a MgO buffer layer.