Interface Tailoring Effect for Heusler Based CPP-GMR with an L1(2)-Type Ag(3)Mg Spacer

Current perpendicular-to-plane (CPP) giant magnetoresistance (GMR) effects are of interest in a possible application of magnetic sensor elements, such as read-head of hard disk drives. To improve the junction performance, the interface tailoring effects were investigated for the Heulser alloy, Co(2)Fe(0.4)Mn(0.6)Si (CFMS), based CPP-GMR junctions with an [Formula: see text]-Ag(3)Mg ordered alloy spacer. Ultra-thin Fe or Mg inserts were utilized for the CFMS/Ag(3)Mg interfaces, and CPP-GMR at low bias current density, J and the J dependence were evaluated for the junctions. Although, at low bias J, MR ratio decreased with increasing the inserts thickness, the device output at high bias J exhibited quite weak dependence on the insert thickness. The output voltages of the order of 4 mV were obtained for the junctions regardless of the insert at an optimal bias J for each. The critical current density [Formula: see text] was evaluated by the shape of MR curves depending on J. [Formula: see text] increased with the insert thicknesses up to 0.45 nm. The enhancement of [Formula: see text] suggests that spin-transfer-torque effect may reduce in the junctions with inserts, which enables a reduction of noise and can be an advantage for device applications.