Large magnetoresistance in current-perpendicular-to-plane pseudo spin-valves using Co2Fe(Ga0.5Ge0.5) Heusler alloy and AgZn spacer

Fully epitaxial pseudo spin-valves (PSVs) using 10-nm-thick Co2Fe(Ga0.5Ge0.5) (CFGG) ferromagnetic layers and a 5-nm-thick AgZn space layer annealed at 630 degrees C show a large current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) output with resistance-change area product, Delta RA, of 21.5 m Omega mu m(2) and MR ratio of 59.6% at room temperature. These values are substantially enhanced to Delta RA of 59.8 m Omega mu m(2) and MR ratio of 200.0% at 10 K. The large MR is attributed to the high spin polarization of the CFGG electrodes with the enhanced L2(1) ordering induced by the atomic diffusion of Zn through the CFGG layers. The CPP-PSV shows relatively large DRA of 10.9m Omega mu m(2) with the MR ratio of 25.6% for the low annealing temperature of 350 degrees C, which is a practically useful feature for read sensor applications. (C) 2015 AIP Publishing LLC.