Spin valve structures

Study of spin current effect in spin valve structures with various insertion layers adjacent to free layer



The physical principle of spintronic effect is derived from different transport properties of the majority and minority spin electrons in a ferromagnetic layer. Therefore, creating and controlling spin current turns out to be a crucial issue in developing spintronic devices. In this study, top type spin valve films with layer sequence of Ta / X / CoFe / Cu / CoFe / IrMn / Ta  (thickness in nanometers and the inserted X is Cu, Pt, and Co, respectively) were grown by a sputtering system and followed by annealing process at 300 ℃. In the present work, we have fabricated and measured spin valve devices by current perpendicular to plane.


Figure 1. Vibrating sample magnetometer measurements -comparison of Pt/Cu/Co-layer Spin Valve films by using vibrating sample magnetometer (VSM). The sheet films with insertion of Cu, Pt, and Co, respectively.


Figure 2. MR & MH loop of sheet film – The MR ratios of (a)  4.05 %, (b)  3.82 % and (c) 5.24 % are obtained from the sheet films with insertion of Cu, Pt, and Co, respectively.


Figure 3. MR measurement from the devices with insertion of Co – (a) Free layer in long axis and Pinned layer in short axis, field is applied in short axis (black) and in long axis (pink). (b) ,(c) Major (black) and minor (green and blue) loops of patterned device for the measurement configuration .


We have fabricated and measured patterned devices with current-perpendicular-plane configuration for studying the spin current effect. Intrinsic property of magnetic reversal were modified in current-perpendicular spin-valve magnetic junctions subject to a pulsed current bias. Patterned devices with current-perpendicular-plane configuration are made for studying the spin current effect.