Localized Spin-Torque Effect in CPP-GMR Sensor With Current-Screen Layer

Spin-torque effect in a CPP-GMR sensor with a current-screen layer was investigated via bias voltage dependence of a MR ratio. Unique behavior related to the current-screen layer structure was observed. The bias voltage dependence of the MR ratio in the current-screen-type CPP-GMR sensor was nearly constant with the variation of the free layer thickness. This appears to be due to the finite exchange transmission length of the tilted magnetic moments in the free layer. The finite exchange transmission length originates from the geometric effect in the current-screen layer.