Subscribe free to our newsletters via your
. 24/7 Space News .


Subscribe free to our newsletters via your




















ENERGY TECH
Generating electric current without energy consumption at room temps
by Staff Writers
Hiroshima, Japan (SPX) Jan 01, 2016


Sb atoms and Te atoms serve as the glue to fix the N-S orientations of Cr atoms in Cr-doped (Sb, Bi)2Te3. This makes the material ferromagnetic.

A group of researchers in Japan and China identified the requirements for the development of new types of extremely low power consumption electric devices by studying Cr-doped (Sb, Bi)2Te3 thin films. This study has been reported in Nature Communications.

At extremely low temperatures, an electric current flows around the edge of the film without energy loss, and under no external magnetic field. This attractive phenomenon is due to the material's ferromagnetic properties; however, so far, it has been unclear how the material gains this property.

For the first time, researchers have revealed the mechanism by which this occurs. "Hopefully, this achievement will lead to the creation of novel materials that operate at room temperature in the future," said Akio Kimura, a professor at Hiroshima University and a member of the research group.

Their achievement can be traced back to the discovery of the quantum Hall effect in the 1980's, where an electric current flows along an edge (or interface) without energy loss. However, this requires both a large external magnetic field and an extremely low temperature.

This is why practical applications have not been possible. Researchers believed that this problem could be overcome with new materials called topological insulators that have ferromagnetic properties such as those found in Cr-doped (Sb, Bi)2Te3.

A topological insulator, predicted in 2005 and first observed in 2007, is neither a metal nor an insulator, and has exotic properties. For example, an electric current is generated only at the surface or the edge of the material, while no electric current is generated inside it.

It looks as if only the surface or the edge of the material has metallic properties, while on the inside it is an insulator.

At extremely low temperatures, a thin film made of Cr-doped (Sb, Bi)2Te3 shows a peculiar phenomenon. As the film itself is ferromagnetic, an electric current is spontaneously generated without an external magnetic field and electric current flows only around the edge of the film without energy loss. However, it was previously unknown as to why Cr-doped (Sb, Bi)2Te3 had such ferromagnetic properties that allowed it to generate electric current.

"That's why we selected the material as the object of our study," said Professor Kimura.

Because Cr is a magnetic element, a Cr atom is equivalent to an atomic-sized magnet. The N-S orientations of such atomic-sized magnets tend to be aligned in parallel by the interactions between the Cr atoms.

When the N-S orientations of Cr atoms in Cr-doped (Sb, Bi)2Te3 are aligned in parallel, the material exhibits ferromagnetism. However, the interatomic distances between the Cr atoms in the material are, in fact, too long to interact sufficiently to make the material ferromagnetic.

The group found that the non-magnetic element atoms, such as the Sb and Te atoms, mediate the magnetic interactions between Cr atoms and serve as the glue to fix the N-S orientations of Cr atoms that face one direction. In addition, the group expects that its finding will provide a way to increase the critical temperature for relevant device applications.

The experiments for this research were mainly conducted at SPring-8. "We would not have achieved perfect results without the facilities and the staff there. They devoted themselves to detecting the extremely subtle magnetism that the atoms of non-magnetic elements exhibit with extremely high precision. I greatly appreciate their efforts," Kimura said.

Ye, M. et al. Carrier-mediated ferromagnetism in the magnetic topological insulator Cr-doped (Sb,Bi)2Te3. Nat. Commun. 6:8913 doi: 10.1038/ncomms9913 (2015).

.


Related Links
Hiroshima University
Powering The World in the 21st Century at Energy-Daily.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
ENERGY TECH
Creation of Jupiter interior, a step towards room temp superconductivity
Osaka, Japan (SPX) Dec 21, 2015
Hydrogen is the most abundant element in the universe, and a major component of stars such as the Sun, as well as gas-giant planets such as Jupiter and Saturn. In recent years, hydrogen's behavior at high temperature and high pressure has been in the realm of interest not only for planetary science, but also for fields such as materials science for the purpose of achieving a hydrogen energy soci ... read more


ENERGY TECH
Russia Postpones Plans on Extensive Moon Exploration Until 2025

South Korea to launch lunar exploration in 2016, land by 2020

Death rumors of Russian lunar program 'greatly exaggerated' - Deputy PM

Rare full moon on Christmas Day

ENERGY TECH
Boulders on a Martian Landslide

NASA suspends March launch of InSight mission to Mars

University researchers test prototype spacesuits at Kennedy

Marshall: Advancing the technology for NASA's Journey to Mars

ENERGY TECH
Congress to NASA: Hurry up on that 'habitation augmentation module'

NASA Reaches New Heights

ISRO's year in review 2015

Astronauts Tour Future White Room, Crew Access Tower

ENERGY TECH
Chinese rover analyzes moon rocks: First new 'ground truth' in 40 years

China launches HD earth observation satellite

Agreement with Chinese Space Tech Lab Will Advance Exploration Goals

China launches new communication satellite

ENERGY TECH
NASA Delivers New Video Experience On ISS

British astronaut dials wrong number on Xmas call from space

Space Station Receives New Space Tool to Help Locate Ammonia Leaks

Two whacks is all it takes for spacewalk repair

ENERGY TECH
Russian Proton-M Carrier Rocket With Express-AMU1 Satellite Launched

45th Space Wing launches ORBCOMM; historically lands first stage booster

SpaceX rocket landing opens 'new door' to space travel

NASA orders second Boeing Crew Mission to ISS

ENERGY TECH
Nearby star hosts closest alien planet in the 'habitable zone'

ALMA reveals planetary construction sites

Monster planet is 'dancing with the stars'

Exoplanets Water Mystery Solved

ENERGY TECH
UCLA researchers create exceptionally strong and lightweight new metal

Port of call at 36,000 KM for in-orbit servicing

Nature's masonry: The first steps in how thin protein sheets form polyhedral shells

Move aside carbon: Boron nitride-reinforced materials are even stronger




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News








The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.