GMR coefficient enhancement of a spin valve structure
AssigneeInternational Business Machines Corporation
InventorHardayal Singh Gill
Life of this patent
Estimating the term…
Abstract
A bottom structure for a spin valve sensor is configured to provide an increased GMR coefficient through the use of a crystallographically aligned seed layer in one embodiment and an improved pinned layer in a further embodiment. This improvement occurs through the avoidance of current shunting of the sensing layers, softening of sensing and pinned layers through even layer texturing, and a stronger coupling between the antiferromagnetic and pinned layers. The improved seed layer of the present invention may be formed with a face-centered cubic (FCC) material having a (111) crystallographic plane parallel to an underlying substrate. One preferred material for use in the seed layer is Ni42Fe50Nb8.
Claims23
A spin valve sensor, comprising:
- a substrate;
- a seed layer positioned above the substrate, the seed layer comprising a first layer comprising a NiFe alloy and a second layer comprising a Ni alloy;
- and a third layer between the first and second layers, the third layer containing a metal selected from the group consisting of Ta and Zr;
- and
- a free layer of a ferromagnetic material positioned above the seed layer.
A spin valve sensor, comprising:
- a substrate;
- a seed layer positioned above the substrate, the seed layer comprising a first layer, a second layer and a third layer;
- the first layer comprising NiFeX, where X is chosen from the group consisting of Nb, Mo, and Cr;
- the second layer comprising a Ni alloy;
- the third layer, between the first and second layers, containing a metal selected from the group consisting of Ta and Zr;
- an antiferromagnetic (AFM) layer positioned above the seed layer;
- a pinned layer formed of a ferromagnetic material and positioned above the antiferromagnetic layer;
- and
- a free layer of a ferromagnetic material positioned above the pinned layer.
A disk drive system, comprising:
- a magnetic recording disk;
- an anti-parallel-pinned spin valve sensor for reading data recorded on the recording disk, the sensor comprising:
- a substrate;
- a seed layer positioned above the substrate, the seed layer comprising:
- a first layer comprising NiFeX, where X is chosen from the group consisting of Nb, Mo, and Cr;
- and
- a second layer positioned between the first layer and the substrate, the second layer comprising a Ni alloy;
- an antiferromagnetic (AFM) layer positioned above the seed layer;
- a pinned layer of a ferromagnetic material positioned above the antiferromagnetic layer, the magnetic orientation of the pinned layer being substantially fixed;
- a spacer layer positioned above the pinned layer;
- a free layer of a ferromagnetic material positioned above the spacer layer, the free layer configured to have an electrical resistance that changes in response to changes in magnetic flux through the free layer;
- and
- a cap layer positioned above the free layer;
- an actuator for moving the spin valve sensor across the magnetic recording disk in order for the spin valve sensor to access different magnetically recorded data on the magnetic recording disk;
- and
- a detector electrically coupled to the spin valve sensor and configured to detect changes in a resistance of the sensor caused by rotation of the magnetization axis of the free ferromagnetic layer relative to the fixed magnetizations of the antiparallel-pinned layer in response to changing magnetic fields induced by the magnetically recorded data.
Dependencies are inferred from the claim text.