Current-perpendicular-to-plane magnetoresistance in epitaxial Co2MnSi/Cr/Co2MnSi trilayers

Current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) of the multilayer thin film using a full-Heusler Co2MnSi (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 (Delta RA) at room temperature was 19 m Omega mu m(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 Delta RA is considered to be the large spin polarization in a high-quality L2(1) CMS film.