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. |
Abstract:
Europium oxide may help usher in next generation of microelectronics
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.
Related News Press |
Physics
Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024
'Sudden death' of quantum fluctuations defies current theories of superconductivity: Study challenges the conventional wisdom of superconducting quantum transitions January 12th, 2024
News and information
Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024
NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Laboratories
A battery’s hopping ions remember where they’ve been: Seen in atomic detail, the seemingly smooth flow of ions through a battery’s electrolyte is surprisingly complicated February 16th, 2024
NRL discovers two-dimensional waveguides February 16th, 2024
Govt.-Legislation/Regulation/Funding/Policy
NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Chemical reactions can scramble quantum information as well as black holes April 5th, 2024
Chip Technology
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Utilizing palladium for addressing contact issues of buried oxide thin film transistors April 5th, 2024
HKUST researchers develop new integration technique for efficient coupling of III-V and silicon February 16th, 2024
Discoveries
Chemical reactions can scramble quantum information as well as black holes April 5th, 2024
New micromaterial releases nanoparticles that selectively destroy cancer cells April 5th, 2024
Utilizing palladium for addressing contact issues of buried oxide thin film transistors April 5th, 2024
Announcements
NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
The latest news from around the world, FREE | ||
Premium Products | ||
Only the news you want to read!
Learn More |
||
Full-service, expert consulting
Learn More |
||