International Business Machines Corporation

Eric Dean Tober

David Darden Chambliss

Ronald Franklin Marks

Robin Frederick Farrow

A magnetoresistive sensor based on a giant magnetoresistance multilayer uses a multilayer structure formed of alternating layers or stripes of ferromagnetic and nonferromagnetic metal that are spontaneously formed or 'self-assembled' laterally on a special template layer. The template layer is a crystalline structure that has a two-fold uniaxial surface, i.e., one that is structurally invariant for a rotation by 180 degrees (and only 180 degrees) about an axis (the symmetry axis) perpendicular to the surface plane. Such a template layer is the (110) surface plane of body-centered-cubic Mo. The alternating stripes of ferromagnetic metal (such as Co or Fe) and nonferromagnetic metal (such as Ag) become spontaneously arranged laterally on the template layer during co-deposition, such as during ultrahigh vaccum evaporation, and are aligned so that the direction of composition modulation, i.e., the direction perpendicular to the alternating stripes is along one of the unique axes of the template layer and in a plane parallel to the template layer. A crystalline base layer may be used beneath the template layer to enhance the growth of the template layer. If the template layer is (110) Mo, then the base layer may be sapphire having its (1 1 2bar 0) plane parallel to the (110) Mo plane.

Self-assembled giant magnetoresistance lateral multilayer for a

A method for forming a magnetoresistive sensor results in the spontaneous formation or 'self-assembly' of a giant magnetoresistance multilayer structure of alternating stripes of ferromagnetic and nonferromagnetic metal that are stacked laterally on a special template layer. The template layer is a crystalline structure that has a two-fold uniaxial surface, i.e., one that is structurally invariant for a rotation by 180 degrees (and only 180 degrees) about an axis (the symmetry axis) perpendicular to the surface plane. Such a template layer is the (110) surface plane of body-centered-cubic Mo. The alternating stripes of ferromagnetic metal (such as Co or Fe) and nonferromagnetic metal (such as Ag) become spontaneously arranged laterally on the template layer during co-deposition, such as during ultrahigh vaccum evaporation, and are aligned so that the direction of compostion modulation, i.e., the direction perpendicular to the alternating stripes is along one of the unique axes of the template layer and in a plane parallel to the template layer. A crystalline base layer may be used beneath the template layer to enhance the growth of the template layer. If the template layer is (110) Mo, then the base layer may be sapphire having its (112 bar 0) plane parallel to the (110) Mo plane.

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Eric Dean Tober