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 L21 structure. The resistance change-area product (ΔRA) at room temperature was 19 mΩ μm2, 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 L21 CMS film. [ABSTRACT FROM AUTHOR]