Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Long-range spin currents induced by heat herald a new era for spintronic applications

09.02.2009
Modern electronics is based on the transport of electrons, generated by a difference in electric voltage. In a bid for faster and smaller electronic devices, researchers have turned to the spin of electrons, or spintronics.

However, sustaining spin currents has proven difficult. Now researchers from the RIKEN Advanced Science Institute in Wako with scientists from Keio University, Yokohoma, and Tohoku University, Sendai, have—for the first time—observed the so-called spin Seebeck effect, which is able to generate pure spin currents across macroscopic distances.

The classic Seebeck effect describes the generation of an electric voltage when the ends of a material are at different temperatures. As such, it is used in thermoelectric devices that convert heat into electricity.

In a similar fashion, as reported by the researchers in Nature1, the spin Seebeck effect reported uses a temperature gradient in a magnetic material to create a flow of electron spins in the absence of any external voltage. As a result, spins of opposite polarization assemble at the two ends of the sample, creating a ‘spin voltage’ caused by the different spin polarizations at both ends. This use of thermal effects in spintronics is novel and unexpected. “The electron spin is usually controlled by magnetic fields, so nobody has thought about a thermoelectric response,” says Wataru Koshibae from the research team.

The discovery of the spin Seebeck effect is enabled by the so-called spin Hall effect. Through interactions between the spin current and the atoms in a metal, electrons of different spin orientations get scattered to opposite ends of the metal, creating an electrical voltage. The spin voltage created by the spin Seebeck effect is then detected by thin platinum sheets placed at both ends of the sample.

Importantly, in this setup the electrons don’t move at all, and only spins travel along the sample. This is markedly different to most other schemes where undesirable parallel electronic currents are unavoidable. In addition, there appears to be no limit to the distances along which spin currents can be sustained. “The spin Seebeck effect occurs in samples almost 1 cm long, much longer than the usual spin current decay lengths of 1 nm,” comments Koshibae.

This first observation of the spin Seebeck effect therefore marks a new era in spintronics and opens the door to novel applications. Long-distance spin current are critical to the realization of spintronic devices, and these results offer the generation of spin currents simply through temperature effects.

Reference

1. Uchida, K., Takahashi, S., Harii, K., Ieda, J., Koshibae, W., Ando, K. Maekawa, S. & Saitoh, E. Observation of the spin Seebeck effect. Nature 455, 778–781 (2008).

The corresponding author for this highlight is based at the RIKEN Theoretical Design Team

Saeko Okada | ResearchSEA
Further information:
http://www.rikenresearch.riken.jp/research/645/
http://www.researchsea.com

More articles from Power and Electrical Engineering:

nachricht Multicrystalline Silicon Solar Cell with 21.9 % Efficiency: Fraunhofer ISE Again Holds World Record
20.02.2017 | Fraunhofer-Institut für Solare Energiesysteme ISE

nachricht Six-legged robots faster than nature-inspired gait
17.02.2017 | Ecole Polytechnique Fédérale de Lausanne

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Switched-on DNA

20.02.2017 | Materials Sciences

Second cause of hidden hearing loss identified

20.02.2017 | Health and Medicine

Prospect for more effective treatment of nerve pain

20.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>