Magnetic field sensor using in situ solid source graphene and graphene induced anti-ferromagnetic coupling and spin filtering
AssigneeThe Government of the United States of America, as represented by the Secretary of the Navy
InventorsOlaf M. J. van't Erve, Enrique Cobas, Shu-Fan Cheng, Berend T. Jonker
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Abstract
A magnetic field sensor based on two anti-ferromagnetically coupled magnetic layers separated by multilayer graphene, prepared in a single sputter chamber without a vacuum break.
Claims10
A magnetic field sensor formed by using in situ solid source graphene, that is absorbed and desorbed on a first ferromagnetic metal creating a graphene multilayer, and using the spin filtering and antiferromagnetic coupling of this graphene multilayer, comprising:
- a substrate comprising silicon wafers and an oxide layer;
- an amorphous carbon layer on the substrate grown by sputtering to control the amount of graphene;
- a first ferromagnetic metal surface grown in situ by sputtering on the amorphous carbon layer;
- wherein said amorphous carbon layer directly contacts said substrate and said first ferromagnetic metal surface
- wherein the first ferromagnetic metal surface comprises NiFe;
- an in-situ graphene film grown on top of the first ferromagnetic layer by first absorbing and then desorbing the amorphous carbon layer or solid source carbon, by in situ annealing of the first ferromagnetic layer;
- wherein the graphene film is multilayer;
- an interface between the multilayer graphene film and the first ferromagnetic metal surface;
- a second ferromagnetic film on the multilayer graphene film;
- wherein the second ferromagnetic film comprises CoFe;
- antiferromagnetic coupling of the first and second ferromagnetic layer due to this graphene multilayer;
- a spin/momentum filtering at the interface between the multilayer graphene film and the first ferromagnetic metal surface;
- and
- a capping layer on the second ferromagnetic film.
A magnetic field sensor formed by using in situ solid source graphene and using graphene induced anti-ferromagnetic coupling and spin filtering formed for the steps comprising:
- providing a substrate comprising silicon wafers and an oxide layer;
- performing DC magnetron sputtering to the substrate comprising silicon wafers and thermal oxide;
- back-sputtering the substrate,
- growing amorphous carbon on the substrate;
- sputtering and growing a first ferromagnetic metal surface on the amorphous carbon;
- wherein said amorphous carbon directly contacts said substrate and said first ferromagnetic metal surface
- wherein the first ferromagnetic metal surface comprises NiFe;
- annealing the substrate and the amorphous carbon and the first ferromagnetic metal surface;
- growing an in-situ graphene film by first absorbing and then desorbing the amorphous carbon layer or solid source carbon, by in situ annealing of the first ferromagnetic layer;
- wherein the graphene film is multilayer;
- an interface between the multilayer graphene film and the first ferromagnetic metal surface;
- sputtering and growing a second ferromagnetic on the multilayer graphene film;
- wherein the second ferromagnetic film comprises CoFe;
- antiferromagnetic coupling between the first and second ferromagnetic layer due to the graphene multilayer;
- a spin/momentum filtering at the interface between the multilayer graphene film and the first ferromagnetic metal surface;
- wherein the first ferromagnetic metal surface comprises NiFe;
- and
- capping the second ferromagnetic film with a platinum layer.
Dependencies are inferred from the claim text.