Synthetic pattern exchange cofiguration for side reading reduction

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 M1;
• 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 M2 and wherein there is a synthetic coupling energy Jsbetween 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 conductive lead layer formed on said ferromagnetic biasing layer;
• and
• wherein said free layer thickness and said biasing layer thickness are determined so that the magnetic moment of said free layer, MF1, and the magnetic moment of said biasing layer, MF2, satisfy the relationship MF2/MF1=1.

A method for fabricating a synthetic, patterned, longitudinally exchange biased GMR sensor with narrow effective trackwidth comprising:

• providing a substrate;
• forming a seed layer on said substrate;
• forming a first layer of antiferromagnetic material on the seed layer, said layer of antiferromagnetic material being a pinning layer;
• forming a synthetic antiferromagnetic pinned layer on said first antiferromagnetic pinning layer;
• forming a non-magnetic spacer layer on said pinned layer;
• forming a ferromagnetic free layer of thickness F1 and magnetic moment MF1 on said non-magnetic spacer layer;
• forming a non-magnetic antiferromagnetically coupling layer on said ferromagnetic free layer;
• forming a ferromagnetic, longitudinal biasing layer of thickness F2, and magnetic moment MF2 on said coupling layer, producing thereby a coupling energy Js and an exchange energy Jex, and wherein the thicknesses F1 and F2 will be determined so that a ratio of the respective magnetic moments MF2/MF1 satisfy a relationship MF2/MF1=(Js+Jex)/Js;
• forming a second antiferromagnetic pinning layer on said longitudinal biasing layer;
• forming a conductive lead layer on said antiferromagnetic layer;
• annealing the resulting structure with a first anneal for a first annealing time, at a first annealing temperature and in a first external magnetic field;
• annealing the resulting structure with a second anneal for a second annealing time, at a second annealing temperature and in a second external magnetic field;
• removing, by an etching process, a central portion of said conductive lead layer and the portion of said second antiferromagnetic pinning layer directly beneath said central portion, exposing, thereby, an upper surface of said longitudinal biasing layer beneath said pinning layer and forming, thereby, two discrete, disconnected and laterally separated segments, laterally and symmetrically disposed to either side of said longitudinal biasing layer and separated by the desired physical trackwidth of said sensor;
• oxidizing the exposed portion of said ferromagnetic longitudinal biasing layer, said oxidation extending the entire width and thickness of said exposed portion and destroying the ferromagnetic properties of said layer and said oxidation being stopped by the upper surface of said non-magnetic antiferromagnetically coupling layer.

A method for fabricating a synthetic, patterned, longitudinally exchange biased GMR sensor with narrow effective trackwidth comprising:

• providing a substrate;
• forming a seed layer on said substrate;
• forming a first layer of antiferromagnetic material on the seed layer, said layer of antiferromagnetic material being a pinning layer;
• forming a synthetic antiferromagnetic pinned layer on said first antiferromagnetic pinning layer;
• forming a non-magnetic spacer layer on said pinned layer;
• forming a ferromagnetic free layer of thickness F1 and magnetic moment MF1 on said non-magnetic spacer layer;
• forming a non-magnetic antiferromagnetically coupling layer on said ferromagnetic free layer;
• forming a ferromagnetic, longitudinal biasing layer of thickness F2, and magnetic moment MF2 on said coupling layer, producing thereby a coupling energy Js, and wherein the thicknesses F1 and F2 will be determined so that a ratio of the respective magnetic moments MF2/MF1 satisfy a relationship MF2/MF1=1;
• forming a conductive lead layer on said longitudinal biasing layer;
• annealing the resulting structure with a first anneal for a first annealing time, at a first annealing temperature and in a first external magnetic field;
• annealing the resulting structure with a second anneal for a second annealing time, at a second annealing temperature and in a second external magnetic field;
• removing, by an etching process, a central portion of said conductive lead layer, exposing, thereby, an upper surface of said longitudinal biasing layer beneath said pinning layer and forming, thereby, two discrete, disconnected and laterally separated segments, laterally and symmetrically disposed to either side of said longitudinal biasing layer and separated by the desired physical trackwidth of said sensor;
• oxidizing the exposed portion of said ferromagnetic longitudinal biasing layer, said oxidation extending the entire width and thickness of said exposed portion and destroying the ferromagnetic properties of said layer and said oxidation being stopped by the upper surface of said non-magnetic antiferromagnetically coupling layer.