Current-perpendicular-to-plane magnetoresistance in epitaxial Co_2MnSi/Cr/Co_2MnSi trilayers

摘要

Current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) of the multilayer thin film using a full-Heusler Co_2MnSi (CMS) phase as ferromagnetic electrodes has been investigated. A multilayer of Cr buffer (10 nm)/CMS (50 nm)/Cr spacer (3 nm)/CMS (10 nm)/Cr cap (3 nm) was grown on a MgO(100) substrate. The 50 nm thick CMS layer which was deposited on the Cr buffer at 573 K was epitaxially grown and had an L2_1 structure. The resistance change-area product (ΔRA) at room temperature was 19 mΩ μm~2, which is one order of magnitude larger than those in previously reported trilayer systems, resulting in the MR ratio of 2.4%. A possible origin of the enhanced ΔRA is considered to be the large spin polarization in a high-quality L2_1 CMS film.