Patent ID: 6469873
Filing Date: 2002-10-22
Classification: B82Y,G11B

Abstract:
A magnetic storage apparatus comprising:a perpendicular magnetic recording medium including a film having an easy magnetization axis in a direction perpendicular to the surface of said film; and a magnetic head including: a first spin valve element including: a first antiferromagnetic film; a first ferromagnetic film having a magnetization direction fixed by exchange coupling with said first antiferromagnetic film; a first non-magnetic film; a second ferromagnetic film having a magnetization direction fixed in a direction antiparallel to said first ferromagnetic film; said first non-magnetic film causing antiferromagnetic coupling between said first ferromagnetic film and said second ferromagnetic film; a first soft magnetic film having a magnetization direction which can be turned depending on the magnetic field applied from said magnetic recording medium; and a second non-magnetic film formed between said second ferromagnetic film and said first soft magnetic film; a second spin valve element including: a second antiferromagnetic film; a third ferromagnetic film having a magnetization direction fixed by exchange coupling with said second antiferromagnetic film; a second soft magnetic film having a magnetization direction which can be turned depending on the magnetic field applied from said magnetic recording medium; and a third non-magnetic film formed between said third ferromagnetic film and said second soft magnetic film, the magnetization direction of said second ferromagnetic film and said third ferromagnetic film being antiparallel; a fifth non-magnetic film provided between said first spin valve element and said second spin valve element with said first soft magnetic film and said second soft magnetic film symmetrically disposed around said fifth non-magnetic film; and wherein the product of the film thickness and saturation magnetization of said first ferromagnetic film is larger than the product of the film thickness and saturation magnetization of said second ferromagnetic film; and a differential circuit including a first amplifier circuit and a second amplifier circuit, each having a different polarity; wherein an output of the first spin valve element is inputted to said first amplifier circuit and an output of the second spin valve element is inputted to said second amplifier circuit.