Patent ID: 6807033
Filing Date: 2004-10-19
Classification: B82Y,G01R,G11B

Abstract:
A magnetic sensor, comprising a synthetic antiferromagnetic layer having first and second wing regions and an active region therebetween, wherein the synthetic antiferromagnetic layer includes:a non-magnetic metal layer having first and second wing region portions and an active region portion therebetween, the non-magnetic metal layer including first and second opposing surfaces; a first ferromagnetic layer adjacent a first surface of the non-magnetic metal layer and having first and second wing region portions and an active region portion therebetween; and a second ferromagnetic layer adjacent the second surface of the non-magnetic metal layer and including a first wing region portion adjacent the first wing region portion of the non-magnetic metal layer and a second wing region portion adjacent the second wing region portion of the non-magnetic metal layer, wherein the second ferromagnetic layer is of adequate thickness such that the magnetic susceptibility of the first and second wing region portions of the first ferromagnetic layer is substantially zero when magnetic signal fields are present only in the first and second wing regions, wherein the first ferromagnetic layer includes a second surface opposite the first surface and wherein the first ferromagnetic layer is a layer of a giant magnetoresistive tri-layer, the giant magnetoresistive tri-layer further comprising: a second non-magnetic metal layer including copper and having first and second opposing surfaces, wherein the first surface of the second non-magnetic metal layer is adjacent the second surface of the first ferromagnetic layer; and a third ferromagnetic layer having first and second opposing surfaces, wherein the first surface of the third ferromagnetic layer is adjacent the second surface of the second non-magnetic metal layer, and including a material selected from the group of nickel-iron, cobalt-iron and nickel-iron-cobalt, and wherein the magnetic sensor further includes a third non-magnetic metal layer having a first and second opposing surfaces, wherein the first surface is adjacent the second surface of the third ferromagnetic layer.