Tunneling magnetoresistance (TMR) read sensor with a long diffusion path and ex-situ interfaces in a sense layer structure
First Claim
1. A read sensor, comprising:
- a barrier layer sandwiched between a lower sensor stack and an upper sensor stack;
the lower sensor stack comprising;
a pinning layer;
a keeper layer structure on the pinning layer;
an antiparallel-coupling layer on the keeper layer structure; and
a reference layer structure on the antiparallel-coupling layer;
the upper sensor stack comprising;
a sense layer structure that includes a first layer comprising CoFe formed on the barrier layer, a second layer consisting of CoFeB having a thickness of 2 to 4.8 nm and formed directly on the first layer and a third layer consisting of NiFe formed directly on the second layer, wherein the total thickness of the first sense layer and the second sense layer is large enough to form a sufficiently long diffusion path to trap Ni atoms thereby preventing Ni atoms from migrating from the third layer to the barrier layer;
wherein the sense structure has a diffusion path (defined as the total thickness of the first and second sense layers) of at least 3.2 nm; and
a cap layer structure on the sense layer structure.
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Abstract
The invention provides a tunneling magnetoresistance (TMR) read sensor with a long diffusion path and ex-situ interfaces in a sense layer structure. The sense layer structure comprises a first sense layer preferably formed of a ferromagnetic Co—Fe film, a second sense layer preferably formed of a ferromagnetic Co—Fe—B film, and a third sense layer preferably formed of a ferromagnetic Ni—Fe film. The sense layer structure has a long diffusion path (defined as a total thickness of the first and second sense layers) and ex-situ interfaces for suppressing unwanted diffusions of Ni atoms. Alternatively, the sense layer structure comprises a first sense layer preferably formed of a ferromagnetic Co—Fe film, a second sense layer preferably formed of a ferromagnetic Co—Fe—B film, a third sense layer preferably formed of a ferromagnetic Co—Fe—B—Hf film, and a fourth sense layer preferably formed of a ferromagnetic Ni—Fe film.
25 Citations
8 Claims
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1. A read sensor, comprising:
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a barrier layer sandwiched between a lower sensor stack and an upper sensor stack; the lower sensor stack comprising; a pinning layer; a keeper layer structure on the pinning layer; an antiparallel-coupling layer on the keeper layer structure; and a reference layer structure on the antiparallel-coupling layer; the upper sensor stack comprising; a sense layer structure that includes a first layer comprising CoFe formed on the barrier layer, a second layer consisting of CoFeB having a thickness of 2 to 4.8 nm and formed directly on the first layer and a third layer consisting of NiFe formed directly on the second layer, wherein the total thickness of the first sense layer and the second sense layer is large enough to form a sufficiently long diffusion path to trap Ni atoms thereby preventing Ni atoms from migrating from the third layer to the barrier layer;
wherein the sense structure has a diffusion path (defined as the total thickness of the first and second sense layers) of at least 3.2 nm; anda cap layer structure on the sense layer structure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification