Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > A particular spin topology in solid-state materials has a strong influence on thermally generated electron transport

Figure 1: Schematic representation of spin chirality. Reversing one of the spins (right) results in reversing the spin chirality.
Figure 1: Schematic representation of spin chirality. Reversing one of the spins (right) results in reversing the spin chirality.

Abstract:
Chirality, or handedness—where an object cannot be superimposed on its mirror image—is found in many physical systems. In the case of electron spin—the smallest magnetic field generated by an electron—the chirality shown by some compounds can be quantified by the solid angle subtended by three nearby spins, and can be controlled by the application of a magnetic field (Fig. 1).

A particular spin topology in solid-state materials has a strong influence on thermally generated electron transport

Japan | Posted on July 25th, 2008

Shigeki Onoda from the RIKEN's Advanced Science Institute (formerly the Discovery Research Institute), Wako, and colleagues from Japan and Hungary have studied the effect of spin chirality on the transport properties in solid-state materials1. Spin chirality has been shown to have an effect on other transport properties, for example in the so-called anomalous Hall effects2, in which no temperature gradient is involved.

"Spin chirality bears a fictitious magnetic field and bends the electron motion driven by the temperature gradient, [thus] introducing a transverse current," explains Onoda. "The direction in which the electron motion is bent depends on the sign of the spin chirality."

In their study, the researchers focussed on whether spin chirality influences the Nernst effect, which describes the generation of an electric current in the direction perpendicular to that of a temperature gradient.

Onoda and colleagues studied a series of compounds named pyrochlore molybdates. Because some members of this family show spin chirality and others do not, they could make direct comparisons.

The comparisons between results on different compounds highlighted the effect of the spin chirality. Specifically, compounds with spin chirality showed an anomalous Nernst effect in a specific temperature range (20-30 K (-253.15- -243.15 °C)), while a compound with no spin chirality showed no effect.

The importance of the result goes beyond the specific case of the class of materials studied. "The observation of this fundamental phenomenon has revealed that a fairly large fictitious magnetic field can be generated in materials by controlling the low-energy degrees of freedom of the spin chirality," says Onoda. "The sign of the spin chirality controls that of the transverse heat/electric current. This is unlike the usual cases of Nernst effects, where [the sign of the transverse current] is exclusively determined by that of the temperature gradient and the applied magnetic field or the magnetization in particular materials." According to the researchers, their study reveals that spin chirality is really a new and promising basic quantity in electron transport phenomena.
Reference

1. Hanasaki, N., Sano, K., Onose, Y., Ohtsuka, T., Iguchi, S., Kézsmárki, I., Miyasaka, S., Onoda, S., Nagaosa, N. & Tokura, Y. Physical Review Letters 100, 106601 (2008). | article |
2. Taguchi, Y., Oohara, Y., Yoshizawa, H., Nagaosa, N. & Tokura, Y. Spin chirality, Berry phase, and anomalous Hall effect in a frustrated ferromagnet. Science 291, 2573-2576 (2001).

####

For more information, please click here

Copyright © Riken

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

A new, tunable device for spintronics: An international team of scientists including physicist Jairo Sinova from the University of Mainz realises a tunable spin-charge converter made of GaAs August 29th, 2014

Nanoscale assembly line August 29th, 2014

New analytical technology reveals 'nanomechanical' surface traits August 29th, 2014

New Vice President Takes Helm at CNSE CMOST: Catherine Gilbert To Lead CNSE Children’s Museum of Science and Technology Through Expansion And Relocation August 29th, 2014

Physics

New technique uses fraction of measurements to efficiently find quantum wave functions August 28th, 2014

Creation of a Highly Efficient Technique to Develop Low-Friction Materials Which Are Drawing Attention in Association with Energy Issues August 26th, 2014

X-ray Laser Probes Tiny Quantum Tornadoes in Superfluid Droplets: SLAC Experiment Reveals Mysterious Order in Liquid Helium August 25th, 2014

Rice physicist emerges as leader in quantum materials research: Nevidomskyy wins both NSF CAREER Award and Cottrell Scholar Award August 20th, 2014

Discoveries

A new, tunable device for spintronics: An international team of scientists including physicist Jairo Sinova from the University of Mainz realises a tunable spin-charge converter made of GaAs August 29th, 2014

Nanoscale assembly line August 29th, 2014

Copper shines as flexible conductor August 29th, 2014

Novel 'butterfly' molecule could build new sensors, photoenergy conversion devices August 28th, 2014

Announcements

A new, tunable device for spintronics: An international team of scientists including physicist Jairo Sinova from the University of Mainz realises a tunable spin-charge converter made of GaAs August 29th, 2014

Nanoscale assembly line August 29th, 2014

New analytical technology reveals 'nanomechanical' surface traits August 29th, 2014

New Vice President Takes Helm at CNSE CMOST: Catherine Gilbert To Lead CNSE Children’s Museum of Science and Technology Through Expansion And Relocation August 29th, 2014

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







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE