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US 9,529,060 B2Granted
Magnetoresistance element with improved response to magnetic fields
AssigneeAllegro MicroSystems, LLC
InventorsClaude Fermon, Myriam Pannetier-Lecoeur, Marie-Claire Cyrille, Cyril Dressler, Paolo Campiglio
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Abstract
A magnetoresistance element has a double pinned arrangement with two antiferromagnetic pinning layers, two pinned layers, and a free layer. A spacer layer between one of the two antiferromagnetic pinning layers and the free layer has a material selected to allow a controllable partial pinning by the one of the two antiferromagnetic pinning layers.
Claims28
A magnetoresistance element, comprising:
- a substrate;
- a first layer disposed over the substrate, the first layer comprising a seed layer;
- a second layer disposed over the first layer, the second layer comprising a first antiferromagnetic pinning layer,
- a third layer disposed over the second layer, the third layer comprising a first pinned layer, wherein a position of the second layer is selected to influence a magnetization of the third layer;
- a fourth layer disposed over the third layer, the fourth layer comprising a first nonmagnetic spacer layer;
- a fifth layer disposed over the fourth layer, the fifth layer comprising a free layer, the free layer having a plurality of magnetic domains, the plurality of magnetic domains comprising:
- a first plurality of magnetic domains with magnetic fields pointing in a first direction;
- and
- a second plurality of magnetic domains with magnetic fields pointing in one or more directions different than the first direction;
- a sixth layer disposed over the fifth layer, the sixth layer comprising a second pinned layer, wherein the sixth layer consists of a single ferromagnetic layer;
- a seventh layer disposed over the sixth layer, the seventh layer comprising a second antiferromagnetic pinning layer, a position of the seventh layer selected to influence a magnetization of the sixth layer, the sixth layer at a selected position relative to the fifth layer, the selected position of the sixth layer relative of the fifth layer resulting in a selected reduction in a quantity of magnetic domains within the second plurality of magnetic domains in the fifth layer without fully pinning the fifth layer;
- and
- an eighth layer disposed between the fifth layer and the sixth and seventh layers taken together, the eighth layer comprising a second nonmagnetic spacer layer, wherein a material of the eighth layer is selected to allow a thickness of the eighth layer to be greater than 0.5 nm while allowing a desired partial pinning between the fifth layer and the sixth layer, wherein the first pinned layer is comprised of:
- a first ferromagnetic pinned layer disposed proximate to the second layer;
- a third nonmagnetic spacer layer disposed over the first ferromagnetic pinned layer;
- and
- a second ferromagnetic pinned layer disposed over the third nonmagnetic spacer layer,
- wherein magnetic field directions in the first and second pinned layers are annealed to be ninety degrees apart, and wherein a magnetic field direction in the second pinned layer is parallel with a magnetic field direction in the second antiferromagnetic pinning layer, and
- wherein the first and second antiferromagnetic pinning layers are both comprised of PtMn.
16 more elements
A method of fabricating a magnetoresistance element, comprising:
- depositing a double pinned magnetoresistance element upon a substrate, the double pinned magnetoresistance element comprising:
- a first antiferromagnetic pinning layer disposed over the substrate;
- a first pinned layer disposed over the antiferromagnetic pinning layer;
- a first nonmagnetic spacer layer disposed over the first pinned layer;
- a free layer disposed over the first nonmagnetic spacer layer;
- a second pinned layer disposed over the free layer, wherein the second pinned layer consists of a single ferromagnetic layer;
- a second antiferromagnetic pinning layer disposed over the second pinned layer;
- and
- a second nonmagnetic spacer layer disposed between the second pinned layer and the free layer, wherein a material of the second nonmagnetic spacer layer is selected to allow a thickness of the second nonmagnetic spacer layer to be greater than 0.5 nm while allowing a desired partial pinning between the second pinned layer and the free layer,
- wherein the first pinned layer is comprised of:
- a first ferromagnetic pinned layer disposed proximate to the second layer;
- a third nonmagnetic spacer layer disposed over the first ferromagnetic pinned layer;
- and
- a second ferromagnetic pinned layer disposed over the third nonmagnetic spacer layer
- wherein magnetic field directions in the first and second pinned layers are annealed to be ninety degrees apart, and wherein a magnetic field direction in the second pinned layer is parallel with a magnetic field direction in the second antiferromagnetic pinning layer, and
- wherein the first and second antiferromagnetic pinning layers are both comprised of PtMn.
13 more elements
Dependencies are inferred from the claim text.