Current-perpendicular-to-plane magnetoresistance in epitaxial Co ₂ MnSiCr Co₂ MnSi trilayers

Current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) of the multilayer thin film using a full-Heusler Co2 MnSi (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 L 21 structure. The resistance change-area product (ΔRA) at room temperature was 19 m μ m2, 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 L 21 CMS film.