Magnetoelectric control of superparamagnetism
AssigneeThe Regents of the University of California
InventorsSarah H. Tolbert, Gregory P. Carman, Scott Keller, Laura Schelhas, Hyungsuk Kim, Joshua Hockel
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Abstract
A magnetoelectric composite device having a free (i.e. switchable) layer of ferromagnetic nanocrystals mechanically coupled a ferroelectric single crystal substrate is presented, wherein application of an electrical field on the composite switches the magnetic state of the switchable layer from a superparamagnetic state having no overall net magnetization to a substantially single-domain ferromagnetic state.
Claims29
A magnetoelectric device, comprising:
- a superparamagnetic element;
- and
- a dielectric element coupled to the superparamagnetic element;
- wherein the superparamagnetic element is coupled to the dielectric element such that presence of an electric field switches the magnetic state of the superparamagnetic element between a superparamagnetic state and a substantially single-domain ferromagnetic state;
- and
- wherein the superparamagnetic state comprises substantially no overall net magnetization.
A multiferroic composite, comprising:
- a switchable superparamagnetic element having an electric-field-induced anisotropy;
- and
- a ferroelectric element coupled to the superparamagnetic element;
- wherein the superparamagnetic element is coupled to the ferroelectric element such that presence of an electric field switches the magnetic state of the superparamagnetic element between a superparamagnetic state and a substantially single-domain ferromagnetic state;
- and
- wherein the superparamagnetic state comprises substantially no overall net magnetization.
A method for switching the magnetic state of a composite, comprising:
- providing a superparamagnetic element having an electric-field-induced anisotropy;
- mechanically coupling the superparamagnetic element to a ferroelectric element;
- and
- applying an electric field to the composite to switch a magnetic state of the superparamagnetic element between a superparamagnetic state and a substantially single-domain ferromagnetic state;
- wherein the superparamagnetic state comprises substantially no overall net magnetization.
Dependencies are inferred from the claim text.