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US 6,661,620 B2Granted
Differential CPP sensor
AssigneeSeagate Technology LLC
InventorsMichael Allen Seigler, Gregory John Parker
Life of this patent
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Abstract
A differential sensor for reading data from a magnetic medium is disclosed. The sensor comprises two GMR multilayer structures biased in opposite directions, such as to show the transitions between binary states recorded on the media as the media flows under the sensor. The biasing of the GMR structures can be accomplished using a synthetic-antiferromagnet.
Claims26
A differential CPP sensor comprising:
- a first GMR multilayer device;
- an interlayer of non-magnetic material adjacent said first GMR multilayer device;
- a second GMR multilayer device adjacent said interlayer of non-magnetic material opposite said first GMR multilayer device;
- and
- a biasing element for biasing said GMR multilayer devices in opposite directions;
- wherein said first and said second GMR multilayer devices each comprises one or more bi-layer devices having a layer of ferromagnetic material and a layer of non-magnetic material;
- and further wherein a given applied magnetic field causes the resistance of said first GMR multilayer and the resistance of said second GMR multilayer to vary inversely.
4 more elements
A differential CPP sensor comprising:
- a first GMR multilayer device;
- an interlayer of non-magnetic material adjacent said first GMR multilayer device;
- a second GMR multilayer device adjacent said interlayer of non-magnetic material opposite said first GMR multilayer device;
- and
- a synthetic anti-ferromagnet for biasing said GMR multilayer devices in opposite directions;
- wherein a given applied magnetic field causes the resistance of said first GMR multilayer and the resistance of said second GMR multilayer to vary inversely.
3 more elements
A disc drive system comprising:
- a magnetic media;
- a write head for writing data on said magnetic media;
- and
- a differential read head comprising:
- a first GMR multilayer device;
- an interlayer of non-magnetic material adjacent said first GMR multilayer device;
- a second GMR multilayer device adjacent said interlayer of non-magnetic material opposite said first GMR multilayer device;
- and
- a biasing element for biasing said GMR multilayer devices in opposite directions;
- wherein said first and said second GMR multilayer devices each comprises one or more bi-layer devices having a layer of ferromagnetic material and a layer of non-magnetic material and further wherein a given applied magnetic field causes the resistance of said first GMR multilayer and the resistance of said second GMR multilayer to vary inversely.
7 more elements
Dependencies are inferred from the claim text.