Carnegie Mellon University

University of Minnesota

Sara A Majetich

Michael McHenry

Jian-Ping Wang

Delin Zhang

Mukund Bapna

Joseph Artman

Stuart Staley

John H Scott

Elaine Brunsman

Tianlong Wen

Scott Kirkpatrick

A magnetic device may include a layer stack. The layer stack may include a first ferromagnetic layer; a non-magnetic spacer layer on the first ferromagnetic layer, where the non-magnetic spacer layer comprises at least one of Ru, Ir, Ta, Cr, W, Mo, Re, Hf, Zr, or V; a second ferromagnetic layer on the non-magnetic spacer layer; and an oxide layer on the second ferromagnetic layer. The magnetic device also may include a voltage source configured to apply a bias voltage across the layer stack to cause switching of a magnetic orientation of the second ferromagnetic layer without application of an external magnetic field or a current. A thickness and composition of the non-magnetic spacer layer may be selected to enable a switching direction of the magnetic orientation of the second ferromagnetic layer to be controlled by a sign of the bias voltage.

Electric field switchable magnetic devices

In one aspect, a method comprises: providing a substrate having at least one layer in which the patterned dot array is to be fabricated; depositing a nanoparticle layer, wherein the nanoparticle layer comprises one or more surfactants and nanoparticles coated with the one or more surfactants; treating the one or more surfactants that coat the nanoparticles and the portions of the one or more surfactants that fill the spaces among the nanoparticles; removing the portions of the one or more surfactants that fill the spaces among the nanoparticles to expose portions of the at least one layer in which the patterned dot array is to be fabricated; etching the exposed portions of the at least one layer in which the patterned dot array is to be fabricated; and removing at least a portion of the nanoparticles.

Pattern transfer with self-assembled nanoparticle assemblies

A metal or alloy nanoparticle is provided which exhibits hysteresis at room temperature having a carbon coating. The nanoparticle has a diameter in the range of approximately 0.5 to 50 nm, and may be crystalline or amorphous. The metal, alloy, or metal carbide nanoparticle is formed by preparing graphite rods which are packed with the magnetic metal or alloy or an oxide of the metal or alloy. The packed graphite rods are subjected to a carbon arc discharge to produce soot containing metal, alloy, or metal carbide nanoparticles and non-magnetic species. The soot is subsequently subjected to a magnetic field gradient to separate the metal, alloy, or metal carbide nanoparticles from the non-magnetic species.

Process for forming nanoparticles

A metal or alloy nanoparticle is provided which exhibits hysteresis at room temperature having a carbon coating. The nanoparticle has a diameter in the range of approximately 0.5 to 50 nm, and may crystalline or amorphous. The metal, alloy, or metal carbide nanoparticle is formed by preparing graphite rods which are packed with the magnetic metal or alloy. or an oxide of the metal or alloy. The packed graphite rods are subjected to a carbon arc discharge to produce soot containing metal, alloy, or metal carbide nanoparticles and non-magnetic species. The spot is subsequently subjected to a magnetic field gradient to separate the metal, alloy, or metal carbide nanoparticles from the non-magnetic species.

Metal, alloy, or metal carbide nanoparticles and a process for forming

A magnetic metal or metal carbide nanoparticle is provided having a carbon coating. The nanoparticle has a diameter in the range of approximately 5 to 60 nm, and may be crystalline or amorphous. The magnetic metal or metal carbide nanoparticle is formed by preparing graphite rods which are packed with a magnetic metal oxide. The packed graphite rods are subjected to a carbon arc discharge to produce soot containing magnetic metal or metal carbide nanoparticles and non-magnetic species. The soot is subsequently subjected to a magnetic field gradient to separate the magnetic metal or metal carbide nanoparticles from the non-magnetic species. Ferromagnetic or paramagnetic compounds are made by starting with graphite rods packed with the oxides of iron, cobalt, nickel and manganese bismuth, or a rare earth element excluding lanthanum, lutetium and promethium, or a paramagnetic transition metal.

Growing community of inventors

Pittsburgh, PA, United States of America

Sara A Majetich