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 Scientists create biodegradable, paper-based biobatteries
08.08.2018 | Binghamton University

nachricht Ricocheting radio waves monitor the tiniest movements in a room
07.08.2018 | Duke University

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: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Im Focus: Lining up surprising behaviors of superconductor with one of the world's strongest magnets

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

Staying in Shape

16.08.2018 | Life Sciences

Diving robots find Antarctic seas exhale surprising amounts of carbon dioxide in winter

16.08.2018 | Earth Sciences

Protein droplets keep neurons at the ready and immune system in balance

16.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>