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:5/26/2016)... 26, 2016  Agriculture nutrients are in the news ... is running their nitrate removal system on ... and coastal regions nationwide are painting the ... widespread issue. NECi Superior Enzymes, a biotechnology ... developed a new, easy to use device that fits ...
(Date:5/26/2016)... ... May 26, 2016 , ... After several promising ... at the City of Knowledge in Panama, a 6 year-old Duchenne’s muscular ... US earlier this year following FDA approval of a second application for a ...
(Date:5/25/2016)... ... May 25, 2016 , ... Thailand’s Board ... BIO 2016 in San Francisco. Located at booth number 7301, representatives from the ... questions and discuss the Thai biotechnology and life sciences sector. , Deputy ...
(Date:5/25/2016)... ... May 25, 2016 , ... Scientists at the University of Athens say ... mesothelioma may be hampering the research that could lead to one good one. Surviving ... read it now. , The team evaluated 98 mesothelioma patients who ...
Breaking Biology Technology:
(Date:4/15/2016)...  A new partnership announced today will help ... in a fraction of the time it takes ... life insurance policies to consumers without requiring inconvenient ... Diagnostics, rapid testing (A1C, Cotinine and HIV) and ... weight, pulse, BMI, and activity data) available at ...
(Date:3/31/2016)... 2016   LegacyXChange, ... "Company") LegacyXChange is excited to release its ... to be launched online site for trading 100% guaranteed ... will also provide potential shareholders a sense of the ... an industry that is notorious for fraud. The video ...
(Date:3/22/2016)... , March 22, 2016 ... report "Electronic Sensors Market for Consumer Industry by Type ... Others), Application (Communication & IT, Entertainment, Home ... Global Forecast to 2022", published by MarketsandMarkets, ... expected to reach USD 26.76 Billion by ...
Breaking Biology News(10 mins):