Patent ID: 7957109
Filing Date: 2011-06-07
Classification: G11B

Abstract:
1. A magnetic head of tunnel magnetoresistance effect type which has between lower and upper magnetic shield layers (both functioning as electrode layers), an antiferromagnetic layer, a pinned layer which has the direction of magnetization pinned by exchange coupling with said antiferromagnetic layer, an insulating layer, and a free layer whose direction of magnetization rotates relatively to external magnetic fields, wherein said antiferromagnetic layer is of an antiferromagnetic substance composed mainly of IrMn, said pinned layer is made up of a first pinned layer of CoFe alloy which is in contact with said antiferromagnetic layer and a second pinned layer of CoFeB alloy which is antiferromagnetically coupled with said first pinned layer, and said first and second pinned layers have the amount of magnetization (represented by M1 and M2, respectively) such that the difference M1−M2 is in the range of 0≦M2−M1≦0.5 (nm·T) and also have the magnetostriction constants (represented by λ1 and λ2, respectively) such that the difference |λ1−λ2| is no larger than 5.0×10