Tunnel junction sensor with an antiferromagnetic (AFM) coupled flux guide

摘要

A magnetic read head includes a tunnel junction sensor that has front and back surfaces that are recessed from the ABS and a flux guide that includes a ferromagnetic flux guide body with front and back surfaces wherein the front surface forms a portion of the ABS and the back surface is magnetically coupled to the tunnel junction sensor. A flux guide body has a middle portion between first and second side portions and first and second antiferromagnetic layers wherein the first antiferromagnetic layer is magnetically coupled to the first side portion and the second antiferromagnetic layer is magnetically coupled to the second side portion for pinning magnetic moments of the first and second side portions so that only a magnetic moment of the middle portion defines a track width of the sensor and responds to field signals from a rotating magnetic disk. The first and second antiferromagnetic layers have side walls which are perpendicular to the ABS and spaced apart by the track width. Each of the front surface of the tunnel junction sensor and the back surface of the flux guide have a width as measured parallel to the ABS and to the major planes of the layers that is greater than the track width.