Patent Number: 6,295,186

Title: Spin-valve magnetoresistive Sensor including a first antiferromagneticlayer for increasing a coercive force and a second antiferromagnetic layerfor imposing a longitudinal bias

Abstract: The present invention provides a spin-valve magnetoresistive sensorcomprising at least two ferromagnetic layers including a first and asecond ferromagnetic layers. A first antiferromagnetic layer is layeredadjacent to the first ferromagnetic layer for increasing the coerciveforce of the first ferromagnetic layer to pin the magnetization directionof the first ferromagnetic layer. A pair of second antiferromagneticlayers are respectively positioned adjacent to the longitudinal ends ofthe second ferromagnetic layer. Further, a pair of third ferromagneticlayers are respectively layered adjacent to said pair of secondantiferromagnetic layers for inducing magnetic anisotropy to pin themagnetization direction of each third ferromagnetic layer in a directionperpendicular to the pinned magnetization direction of the firstferromagnetic layer, thereby imposing a longitudinal bias on the secondferromagnetic layer to stabilize magnetic domains therein in order tosuppress Barkhausen noise. The magnetization direction of the secondferromagnetic layer remains free to rotate in accordance with thedirection of an external magnetic field, thereby changing the electricalresistance of the sensor.

Inventors: Hasegawa; Naoya (Niigata-ken, JP), Saito; Masamichi (Niigata-ken, JP), Makino; Akihiro (Niigata-ken, JP)

Assignee:

International Classification:

Expiration Date: 09/25/2013