Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Silver keeps the electrons spinning

13.02.2008
The future of computing may emerge not from electronics, but from ‘spintronics’. This new technology relies on the transport of electrons whose quantum spin states—or internal angular momentum—are all the same.

Silver can transport spin-polarized electrons, making it ideal for the non-magnetic components in ‘spintronic’ devices

The future of computing may emerge not from electronics, but from ‘spintronics’. This new technology relies on the transport of electrons whose quantum spin states—or internal angular momentum—are all the same. YoshiChika Otani and Takashi Kimura at the University of Tokyo and the RIKEN Frontier Research System in Wako have been searching for the best materials to carry this ‘spin polarization’, and it appears that silver is a strong candidate1.

Many useful spin polarization phenomena arise in hybrid devices comprising both magnetic and non-magnetic materials. However, when spin-polarized electrons pass from a magnet into a non-magnet, they quickly lose their spin polarization in a process called spin-flip scattering. Therefore, one of the most crucial parameters for spintronics is the spin diffusion length of the non-magnet: the length that electrons travel before all their spin polarization is lost.

The RIKEN team built devices called lateral spin valves to test the spin diffusion lengths of different non-magnetic metals: copper, aluminum, and now silver. They found that the spin polarization of electrons remained very high after passing through a silver wire—implying that silver has a long spin diffusion length.

The result contradicts previous work by a group in the US2, who predicted that silver has a very short diffusion length. Otani and Kimura believe this is because the US team did not take account of spin diffusion at the interfaces between the silver wire and the magnetic detectors used in their experiment.

By including the diffusion processes in their calculations, Otani and Kimura have proven that silver actually has a longer spin diffusion length than any other material studied so far. “What we found was quite different, demonstrating that our common understanding about the spin diffusion process was correct,” says Otani.

In related work, the RIKEN team recently developed the first method that provides complete control over the direction of spin polarization in copper, by using two spin injection needles3. Otani and Kimura believe their device could work just as well, if not better, with silver. However it is more difficult to fabricate devices from silver, so they hope to experiment with other materials soon.

“Our future target is to develop ‘spin current circuits’ that manipulate the spin polarization as well as spin angular momentums,” says Otani. “This may be applied to the next generation of memory or logic circuit technology.”

1. Kimura, T. & Otani, Y. Large spin accumulation in a permalloy-silver lateral spin valve. Physical Review Letters 99, 196604 (2007).

2. Godfrey, R. & Johnson, M. Spin injection in mesoscopic silver wires: experimental test of resistance mismatch. Physical Review Letters 96, 136601 (2006).

3. Kimura, T., Otani, Y.-C. & Levy, P.M. Electrical control of the direction of spin accumulation. Physical Review Letters 99, 166601 (2007).

Saeko Okada | ResearchSEA
Further information:
http://www.researchsea.com
http://www.riken.jp

More articles from Information Technology:

nachricht A novel hybrid UAV that may change the way people operate drones
28.03.2017 | Science China Press

nachricht Timing a space laser with a NASA-style stopwatch
28.03.2017 | NASA/Goddard Space Flight Center

All articles from Information Technology >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Transport of molecular motors into cilia

28.03.2017 | Life Sciences

A novel hybrid UAV that may change the way people operate drones

28.03.2017 | Information Technology

NASA spacecraft investigate clues in radiation belts

28.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>