Oxide interface displaying electronically controllable ferromagnetism
AssigneeUniversity of Pittsburgh—Of the Commonwealth System of Higher Education
InventorsJeremy Levy, Feng Bi, Patrick R. Irvin
Life of this patent
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Abstract
A structure includes an electronically controllable ferromagnetic oxide structure that includes at least three layers. The first layer comprises STO. The second layer has a thickness of at least about 3 unit cells, said thickness being in a direction substantially perpendicular to the interface between the first and second layers. The third layer is in contact with either the first layer or the second layer or both, and is capable of altering the charge carrier density at the interface between the first layer and the second layer. The interface between the first and second layers is capable of exhibiting electronically controlled ferromagnetism.
Claims16
A method of electronically weakening or removing a ferromagnetic state at an interface between a first and a second layer of a multi-layered oxide structure, the method comprising establishing a voltage difference between the interface and a Material in contact with at least one layer of the multi-layered oxide structure, wherein:
- (a) the voltage difference is sufficient to increase the charge carrier density at the interface between the first and second layers of the oxide structure;
- (b) the first layer comprises SrTiO3;
- (c) the second layer comprises at least one of LaAlO3, LaTiO3, EuTiO3, Al2O3, and GaTiO3, and has a thickness of at least about 4 unit cells, the thickness being in a direction substantially perpendicular to the interface between the first and second layers;
- and
- (d) the interface between the first and second layers of the oxide structure is capable of exhibiting electronically controlled ferromagnetization wherein the interface is defined by a plane between the first and second layers and is configured to switch between a ferromagnetic and a non-ferromagnetic state.
A method of electronically establishing an anisotropic ferromagnetic state substantially in a direction {right arrow over (B)} at an interface between a first layer and a second layer of a multi-layered oxide structure, the method comprising establishing a voltage difference between the interface and a material in contact with at least one layer of the multi-layered oxide structure, wherein:
- (a) the voltage difference is sufficient to decrease the charge carrier density at the interface between the first and second layers of the oxide structure;
- (b) the step of establishing a voltage difference is performed while a magnetic field B substantially in a direction {right arrow over (B)} is present at the interface between the first and second layers;
- (c) the first layer of the oxide structure comprises at least one of LaAlO3, LaTiO3, EuTiO3, Al2O3, and GaTiO3, and comprises SrTiO3;
- (d) the second layer of the oxide structure has a thickness at least about 4 unit cells thick, the thickness being in a direction substantially perpendicular to the interface between the first layer and second layer;
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- (e) the interface between the first and second layers of the oxide structure exhibits substantially no ferromagnetization immediately prior to the step of establishing a voltage difference wherein the interface is defined by a plane between the first and second layers and is configured to switch between a ferromagnetic and a non-ferromagnetic state.
Dependencies are inferred from the claim text.