| 摘要 |
A spin valve (SV) magnetoresistive sensor is provided having an AP-pinned layer, an AP-coupled free layer and a non-magnetic electrically conductive spacer layer sandwiched between the AP-pinned layer and the free layer. The AP-pinned layer comprises first and second ferromagnetic layers separated by an antiparallel coupling (APC) layer. The AP-coupled free layer comprises a third ferromagnetic layer of Co-Fe adjacent to the spacer layer, a fourth ferromagnetic layer of Co-Fe-Hf-O and an APC layer sandwiched between the third and fourth ferromagnetic layers. The easy axis of the Co-Fe third ferromagnetic layer has a transverse orientation while the easy axis of the Co-Fe-Hf-O fourth ferromagnetic layer has a longitudinal orientation due to its higher thermal stability resulting in a low net intrinsic uniaxial anisotropy Hk for the AP-coupled free layer. The Co-Fe-Hf-O material of the fourth ferromagnetic layer has high resistivity resulting in reduced sense current shunting by the free layer. In addition, the metal oxide material of the fourth ferromagnetic layer is known to cause specular scattering of electrons. The reduced sense current shunting and the specular scattering of electrons both contribute to improving the GMR coefficient of the SV sensor.
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