| 摘要 |
A fully-pinned, flux-closed spin valve (SV) magnetoresistive sensor having a reference (pinned) layer with magnetization fixed by a first antiferromagnetic (AFM1) layer, and a keeper layer with magnetization fixed by a second antiferromagnetic (AFM2) layer. The magnetization of the keeper layer is saturated and fixed in an antiparallel orientation to the pinned layer magnetization by an exchange interaction with the AFM2 layer. The magnetic moments of the pinned layer and the keeper layer are approximately matched to form a flux-closed magnetic configuration wherein demagnetizing fields in the pinned layer are largely canceled and magnetostatic interaction with the free layer is reduced. Saturation of the keeper layer magnetization by exchange coupling with the AFM2 layer eliminates or reduces magnetization canting at the edges of the keeper layer which can result in signal field shunting through the keeper layer. AFM1 and AFM2 layers may be formed of the same antiferromagnetic material, such as NiO, or alternatively may be formed of different antiferromagnetic materials, such as Ni-Mn and NiO, respectively.
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