Nanodevices for Spintronics and Methods of Using Same
(a) Electronic band structure in the hexagonal carbon layer of graphene. Zero magnetic field results in a linear 2D dispersion, a and b define triangular lattice of a honeycomb graphene layer containing two C atoms. Fermi “surface” consists of two inequivalent points K and K′ (valleys). (b) Magnetic field H parallel to graphene layer introduces Zeeman splitting gμBH between the bands with parallel (P) and antiparallel (AP) spin. P and AP bands acquire congruent Fermi-surfaces of hole- and electron-type respectively.
Graphene magnet multilayers (GMMs) are employed to facilitate development of spintronic devices. Spintronics is a field in which the spin of charge carriers is used in addition to their electrical charge to create small and energy efficient electronic devices. Current spintronic devices include magnetic field sensing devices used in hard drives and magnetic random access memory (MRAM), based on the properties of magnetic multilayers.Description
This invention includes a description of a series of spintronic devices that would utilize spinpolarized charge transport in graphene/antiferromagnetic/ferromagnetic multilayers. Among the devices proposed are (re-)writable microchips, electric current polarizers; spin inverters, and spintronic tunnel junctions, quantum interference devices, transistors, and logic gates.Benefits
Spintronics could open the way to a dramatic increase in the productivity of electronic devices operating at the nanoscale. Progress in miniaturization and increasing efficiency is approaching a fundamental technological limit imposed by the atomic structure of matter. Once circuit scale approaches the size of a few atoms or a single atom, you simply cannot make them any smaller. To move beyond this limit, spintronics takes advantage of an electron's "quantum spin" in addition to its electric charge. By aligning the spins of multiple electrons so they all point the same way - known as polarization – it is possible to create a current of spins in addition to a current of charges. Using magnetism for spin manipulation in graphene also opens exciting possibilities for creating active, re-writable and re-configurable devices whose function changes depending on the magnetization pattern written on the magnetic medium.Applications and Industries
Large-scale manufacturing will require development of robust techniques for forming and patterning multiple ultrathin layers of materials with varying physical properties.More Information
Materials for Making "Spintronic" Devices, Pushing the development of electronics beyond the limits of electric charge,” April 25, 2007, available at http://www.bnl.gov/bnlweb/pubaf/pr/PR_display.asp?prID=07-49)Patents and Patent Applications
|Title and Abstract||
Nanodevices for spintronics and methods of using same
Graphene magnet multilayers (GMMs) are employed to facilitate development of spintronic devices. The GMMs can include a sheet of monolayer (ML) or few-layer (FL) graphene in contact with a magnetic material, such as a ferromagnetic (FM) or an antiferromagnetic material. Electrode terminals can be disposed on the GMMs to be in electrical contact with the graphene. A magnetic field effect is induced in the graphene sheet based on an exchange magnetic field resulting from a magnetization of the magnetic material which is in contact with graphene. Electrical characteristics of the graphene can be manipulated based on the magnetization of the magnetic material in the GMM.
|Brookhaven National Laboratory||02/19/2013
|Technology ID||Development Stage||Availability||Published||Last Updated|