Nanotechnology Now





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Argonne scientists pinpoint mechanism to increase magnetic response of ferromagnetic semiconductor under high pressure

A ferromagnetic-semiconductor europium oxide sample is subjected to high pressures in a diamond anvil cell. The electronic structure is simultaneously probed with circularly polarized X-rays at the Advanced Photon Source, revealing the mechanism responsible for the strengthening of magnetic interactions under pressure.
A ferromagnetic-semiconductor europium oxide sample is subjected to high pressures in a diamond anvil cell. The electronic structure is simultaneously probed with circularly polarized X-rays at the Advanced Photon Source, revealing the mechanism responsible for the strengthening of magnetic interactions under pressure.

Abstract:
Europium oxide may help usher in next generation of microelectronics

Argonne scientists pinpoint mechanism to increase magnetic response of ferromagnetic semiconductor under high pressure

ARGONNE, IL | Posted on March 2nd, 2009

When squeezed, electrons increase their ability to move around. In compounds such as semiconductors and electrical insulators, such squeezing can dramatically change the electrical and magnetic properties.

Under ambient pressure, europium oxide (EuO) becomes ferromagnetic only below 69 Kelvin, limiting its applications. However, its magnetic ordering temperature is known to increase with pressure, reaching 200 Kelvin when squeezed by 150,000 atmospheres. The relevant changes in electronic structure responsible for such dramatic changes, however, remained elusive until recently.

Now scientists at the U.S. Department of Energy's Argonne National Laboratory have manipulated electron mobility and pinpointed the mechanism controlling the strength of magnetic interactions and, hence, the material's magnetic ordering temperature.

"EuO is a ferromagnetic semiconductor and is a material that can carry spin polarized currents, which is an integral element of future devices aimed at manipulating both the spin and the charge of electrons in new generation microelectronics," said Argonne postdoctoral researcher Narcizo Souza-Neto.

Using powerful X-rays from the Advanced Photon Source to probe the material's electronic structure under pressure, Souza-Neto and Argonne physicist Daniel Haskel reported in the February 6 issue of Physical Review Letters that localized, 100 percent polarized Eu 4f electrons become mobile under pressure by hybridizing with neighboring, extended electronic states. The increased mobility enhances the indirect magnetic coupling between Eu spins resulting in a three-fold increase in the ordering temperature. The paper, "Pressure-induced electronic mixing and enhancement of ferromagnetic ordering in EuX (X=O,S,Se,Te) magnetic semiconductors," is available online.

While the need for large applied pressures may seem a burden for applications, large compressive strains can be generated at interfacial regions in EuO films by varying the mismatch in lattice parameter with selected substrates. By pinpointing the mechanism the research provides a road map for manipulating the ordering temperatures in this and related materials, e.g., through strain or chemical substitutions with the ultimate goal of reaching 300 Kelvin (room temperature).

"Manipulation of strain," Haskel said, "adds a new dimension to the design of novel devices based on injection, transport and detection of high spin-polarized currents in magnetic/semiconductor hybrid structures."

Other authors in the paper are graduate student Yuan-Chieh Tseng (Northwestern University) and Gerard Lapertot (CEA-Grenoble).

Funding for this research was provided by the U.S. Department of Energy's Office of Science, the single largest supporter of basic research in the physical sciences in the United States.

####

About Argonne National Laboratory
Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation's first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America 's scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy's Office of Science.

Follow Argonne on Twitter at twitter.com/argonne.

For more information, please click here

Contacts:
Brock Cooper
630/252-5565

Copyright © Argonne National Laboratory

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Stanford breakthrough heralds super-efficient light-based computers: Light can transmit more data while consuming far less power than electricity, and an engineering feat brings optical data transport closer to replacing wires May 29th, 2015

Donuts, math, and superdense teleportation of quantum information May 29th, 2015

OSU researchers prove magnetism can control heat, sound: Team leverages OSC services to help confirm, interpret experimental findings May 29th, 2015

Two UCSB Professors Receive Early Career Research Awards: The Department of Energy’s award for young scientists acknowledges UC Santa Barbara’s standing as a top tier research institution May 29th, 2015

Physics

Donuts, math, and superdense teleportation of quantum information May 29th, 2015

OSU researchers prove magnetism can control heat, sound: Team leverages OSC services to help confirm, interpret experimental findings May 29th, 2015

How spacetime is built by quantum entanglement: New insight into unification of general relativity and quantum mechanics May 28th, 2015

Squeezed quantum cats May 28th, 2015

Laboratories

Linking superconductivity and structure May 28th, 2015

Collaboration could lead to biodegradable computer chips May 28th, 2015

Govt.-Legislation/Regulation/Funding/Policy

OSU researchers prove magnetism can control heat, sound: Team leverages OSC services to help confirm, interpret experimental findings May 29th, 2015

Physicists precisely measure interaction between atoms and carbon surfaces May 28th, 2015

Linking superconductivity and structure May 28th, 2015

Chemists discover key reaction mechanism behind the highly touted sodium-oxygen battery May 28th, 2015

Chip Technology

Stanford breakthrough heralds super-efficient light-based computers: Light can transmit more data while consuming far less power than electricity, and an engineering feat brings optical data transport closer to replacing wires May 29th, 2015

New chip makes testing for antibiotic-resistant bacteria faster, easier: Researchers at the University of Toronto design diagnostic chip to reduce testing time from days to one hour, allowing doctors to pick the right antibiotic the first time May 28th, 2015

Collaboration could lead to biodegradable computer chips May 28th, 2015

Physicists solve quantum tunneling mystery: ANU media release: An international team of scientists studying ultrafast physics have solved a mystery of quantum mechanics, and found that quantum tunneling is an instantaneous process May 27th, 2015

Discoveries

Stanford breakthrough heralds super-efficient light-based computers: Light can transmit more data while consuming far less power than electricity, and an engineering feat brings optical data transport closer to replacing wires May 29th, 2015

Donuts, math, and superdense teleportation of quantum information May 29th, 2015

OSU researchers prove magnetism can control heat, sound: Team leverages OSC services to help confirm, interpret experimental findings May 29th, 2015

New technique speeds nanoMRI imaging: Multiplexing technique for nanoscale magnetic resonance imaging developed by researchers in Switzerland cuts normal scan time from two weeks to two days May 28th, 2015

Announcements

Stanford breakthrough heralds super-efficient light-based computers: Light can transmit more data while consuming far less power than electricity, and an engineering feat brings optical data transport closer to replacing wires May 29th, 2015

Donuts, math, and superdense teleportation of quantum information May 29th, 2015

OSU researchers prove magnetism can control heat, sound: Team leverages OSC services to help confirm, interpret experimental findings May 29th, 2015

Two UCSB Professors Receive Early Career Research Awards: The Department of Energy’s award for young scientists acknowledges UC Santa Barbara’s standing as a top tier research institution May 29th, 2015

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project