Effect of Current Confined Path on Spin Torque Noise in CPP-GMR Heads with a Current Screen Layer

Abstract

We investigated the effect of current-confined-path on spin-torque noise in current-perpendicular-to-the-plane giant-magnetoresistive (CPP-GMR) heads with a current screen layer (a nano oxide layer having current-confined-paths). We found that the current screen structure is effective in suppressing the spin-torque noise. Because, magnetization fluctuation in conductive areas can be reduced by magnetic coupling with magnetization in nonconductive areas. To reduce spin-torque noise, it is effective to reduce the area of each metallic nano-hole while keeping the total conductive area constant, since the magnetic coupling between the magnetization in conductive areas and that in nonconductive areas is enhanced.