Navigation Links
A 50-year quest to isolate the thermoelectric effect is now over: Magnon drag unveiled
Date:12/18/2011

As electrons move past atoms in a solid, their charge distorts the nearby lattice and can create a wave. Reciprocally, a wave in the lattice affects the electrons motion, in analogy to a wave in the sea that pushes a surfer riding it. This interaction results in a thermoelectric effect that was first observed during the 1950s and has come to be known as phonon-drag, because it can be quantified from the flow of lattice-wave quanta (phonons) that occurs over the temperature gradient.

Soon after the discovery of the phonon drag, an analogous phenomenon was predicted to appear in magnetic materials: the so called magnon drag. In a magnetic material the intrinsic magnetic moment or spin of the electrons arrange in an organized fashion. In ferromagnets, the spins maintain a parallel orientation. If a distortion in the preferred spin orientation occurs, a spin wave is created that could affect electron motion. It is therefore reasonable to expect that the flow of magnons (spin-wave quanta) could also drag the electrons.

Despite the similarities with phonon drag, the observation of the magnon drag has been elusive, and only a few indirect indications of its existence have been reported over the years. The main reason being the presence of other thermoelectric effects, most notably the phonon drag, that make it difficult to discriminate its contribution to the thermopower.

Researchers of ICNs Physics and Engineering of Nanodevices Group, Marius V. Costache, Germn Bridoux, Ingmar Neumann and group leader ICREA Prof. Sergio O. Valenzuela used a unique device geometry to discriminate the magnon drag from other thermoelectric effects. The device resembles a thermopile formed by a large number of pairs of ferromagnetic wires placed between a hot and a cold source and connected thermally in parallel and electrically in series. By controlling the relative orientation of the magnetization in pairs of wires, the magnon drag can be studied independently of the electron and phonon drag thermoelectric effects.

The work is very timely as thermoelectric effects in spin-electronics (spintronics) are gathering increasing attention as a means of managing heat in nanoscale structures and of controlling spin information by using heat flow. Measurements as a function of temperature reveal the effect on magnon drag following a variation of magnon and phonon populations. This information is crucial to understand the physics of thermal spin transport. It both provides invaluable opportunities to gather knowledge about electron-magnon interactions and may be beneficial for energy conversion applications and for the search of novel pathways towards transporting spin information.


'/>"/>
Contact: Prof. Dr. Sergio O. Valenzuela
sov@mit.edu
34-935-814-408
Institut Catal de Nanotecnologia
Source:Eurekalert

Related biology technology :

1. University of Dayton Study Overturns 250-Year-Old Belief About Effects of Age, Repeated Injury on Tissue Regeneration
2. Questcor Pharmaceuticals to Present at the Oppenheimer Healthcare Conference on December 13, 2011
3. Quest Diagnostics CE Marks Simplexa™ Test for Cytomegalovirus for Sale in Europe
4. Quest Diagnostics Encourages Denver Area Residents to Enroll in Historic American Cancer Society Prevention Study November 8th - 19th
5. "Tomorrows Health" TV Series Showing the Life Science Industrys Quest to Save and Improve Lives, to Air on Select NBC Stations
6. Quest Diagnostics Initiates CEO Succession Process
7. Diamonds, silver and the quest for single photons
8. Maryland Stem Cell Research Commission Issues 2012 Requests for Applications (RFAs)
9. Questcor Pharmaceuticals to Present at Upcoming Investor Conferences in September
10. HDS International Comments on Front-end Carbon Sequestration Technologies
11. Quest Diagnostics and Genomic Vision Form Strategic Collaboration to Develop Genome-based Laboratory Tests
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:10/11/2017)... ... October 11, 2017 , ... Singh Biotechnology ... drug designation to SBT-100, its novel anti-STAT3 (Signal Transducer and Activator of Transcription ... is able to cross the cell membrane and bind intracellular STAT3 and inhibit ...
(Date:10/10/2017)... ... October 10, 2017 , ... Dr. Bob Harman, founder and ... San Diego Rotary Club. The event entitled “Stem Cells and Their ... 300+ attendees. Dr. Harman, DVM, MPVM was joined by two human doctors: Peter ...
(Date:10/10/2017)... ... October 10, 2017 , ... The Pittcon Program Committee is ... honoring scientists who have made outstanding contributions to analytical chemistry and applied spectroscopy. ... world’s leading conference and exposition for laboratory science, which will be held February ...
(Date:10/9/2017)... , ... October 09, 2017 , ... ... four-tiered line of medical marijuana products targeting the needs of consumers who are ... of Kindred takes place in Phoenix, Arizona. , As operators of two successful ...
Breaking Biology Technology:
(Date:7/20/2017)... July 20, 2017 Delta (NYSE: DAL ) customers ... Delta aircraft at Reagan Washington National Airport (DCA). ... Delta launches biometrics to board aircraft ... Delta,s biometric boarding pass ... is now integrated into the boarding process to allow eligible Delta ...
(Date:6/14/2017)... PARIS , June 15, 2017  IBM (NYSE: IBM ... the international tech event dedicated to developing collaboration between startups ... on June 15-17. During the event, nine startups will ... deliver value in various industries. ... in the international market, with a 30 percent increase in ...
(Date:5/16/2017)... , May 16, 2017   Bridge ... health organizations, and MD EMR Systems , ... development partner for GE, have established a partnership ... Portal product and the GE Centricity™ products, including ... EMR. These new integrations will ...
Breaking Biology News(10 mins):