Patent ID: 7184248

Claim:
A synthetic, patterned, longitudinally exchange biased GMR sensor with narrow effective trackwidth and reduced side reading comprising: a substrate; a first layer of antiferromagnetic material formed on the substrate, said layer being a pinning layer; a synthetic antiferromagnetic pinned layer formed on said antiferromagnetic pinning layer; a non-magnetic spacer layer formed on said pinned layer; a ferromagnetic free layer formed on said non-magnetic spacer layer, said free layer having a free layer thickness and a free layer magnetic moment M 1 ; a non-magnetic antiferromagnetically coupling layer formed on said ferromagnetic free layer; a patterned, ferromagnetic, longitudinal biasing layer formed on said coupling layer, said biasing layer being formed as two discrete, disconnected and laterally separated segments, laterally and symmetrically disposed to either side of the antiferromagnetically coupling layer and wherein the separation of said segments defines a physical trackwidth and wherein said biasing layer has a biasing layer thickness, a biasing layer magnetic moment M 2 and wherein there is a synthetic coupling energy J s between said biasing layer and said free layer and wherein said longitudinal biasing layer is antiferromagnetically coupled to said free layer through said antiferromagnetically coupling layer; a second antiferromagnetic layer formed on said patterned, longitudinal biasing layer and coexstensive with it, said second antiferromagnetic layer being exchange coupled to said longitudinal biasing layer and there being an exchange energy, J ex , between said second antiferromagnetic layer and said biasing layer; a conductive lead layer formed on said antiferromagnetic layer; and wherein said free layer thickness and said biasing layer thickness are determined so that the magnetic moment of said free layer, M F1 , and the magnetic moment of said biasing layer, M F2 , satisfy the relationship M F2 /M F1 =(J s +J ex )/J s .