Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

International team of scientists unveils fundamental properties of spin Seebeck effect

29.07.2016

Direct correlation between temperature dependent generation of spin currents and atomic composition of interfaces found

Thermoelectric effects are a fundamental building block for the conception and development of new processes for information processing. They enable to re-use waste heat obtained in different processes for the operation of respective devices and thus contribute to the establishment of more energy-efficient, ecofriendly processes. A promising representative of this effect category is the so-called spin Seebeck effect, which became prominent within recent years. This effect allows to convert waste heat into spin currents and thereby to transport energy as well as information in magnetic, electrically insulating materials. Physicists of Johannes Gutenberg University Mainz (JGU) in Germany together with their colleagues from Glasgow University in Scotland now succeeded to reveal essential properties of this yet to be fully understood effect. Their findings contribute to a more thorough understanding of the underlying processes of this effect and thereby support its further development for first applications. The research work has been published in the journal Physical Review X.


Thermally excited spin waves carry a spin current from the ferromagnet (YIG in this case) into the metal layer. Depending on the YIG thickness and the interface condition the amplitude of the spin current as well as transmission properties change.

ill/©: Joel Cramer, JGU

The spin Seebeck effect belongs to the category of spin-thermoelectric effects. Previous work of the physicists at Mainz University in collaboration with colleagues from the University of Konstanz and the Massachusetts Institute of Technology (MIT) has shown that the creation of a thermal non-equilibrium leads to the creation of magnetic waves, so-called magnons, within magnetic materials. These transport both energy and torque and thus are able to induce a voltage signal in adjacent metal thin films.

By means of material-dependent measurements over a wide temperature range and with a varied thickness of the employed magnetic material, a direct correlation between the amplitude of the voltage signal and the intrinsic properties of magnons was/could be identified. Furthermore, it was/could be shown that the temperature dependence of the voltage generation efficiency additionally depends strongly on the atomic structure of the interface between magnetic material and metal thin film.

"Step by step answers to the open questions about the fundamental processes of the spin Seebeck effect are given. Our results yield an essential contribution for the development of the aspiring field of Magnon Spintronics", said Joel Cramer, co-author of the publication and stipend of the Graduate School of Excellence "Materials Science in Mainz" (MAINZ).

Professor Mathias Kläui added: "I am very glad that by means of the intensive collaboration with our colleagues we were able to correlate the transport of spins with the microscopic, atomistic structure. The cooperation with our colleagues from Glasgow already led to several mutual publications and an active exchange with leading groups from abroad is one of the central measures of our Graduate School of Excellence."

Establishment of the MAINZ Graduate School was approved through the Excellence Initiative by the German Federal and State Governments to Promote Science and Research at German Universities in 2007 and its funding was extended in the second round in 2012. It consists of work groups from Johannes Gutenberg University Mainz, TU Kaiserslautern, and the Max Planck Institute for Polymer Research in Mainz. One of its focal research areas is spintronics, where cooperation with leading international partners plays an important role.

Publication:
Er-Jia Guo et al.
Influence of thickness and interface on the low-temperature enhancement of the spin Seebeck effect in YIG films
Physical Review X 6, 031012 (2016)
DOI: 10.1103/PhysRevX.6.031012


Further information:
Professor Dr. Mathias Kläui
Condensed Matter Theory Group
Institute of Physics
Johannes Gutenberg University Mainz
55099 Mainz, GERMANY
phone +49 6131 39-23633
e-mail: klaeui@uni-mainz.de
http://www.klaeui-lab.physik.uni-mainz.de/308.php

Graduate School of Excellence Materials Science in Mainz (MAINZ)
Johannes Gutenberg University Mainz
55099 Mainz, GERMANY
phone +49 6131 39-26984
fax +49 6131 39-26983
e-mail: mainz@uni-mainz.de
http://www.mainz.uni-mainz.de/

Weitere Informationen:

http://journals.aps.org/prx/abstract/10.1103/PhysRevX.6.031012 – Article in Physical Review X ;
http://www.uni-mainz.de/presse/20114_ENG_HTML.php – press release "Researchers present new findings on magnetic spin waves", 10 Feb. 2016 ;
http://www.uni-mainz.de/presse/19572_ENG_HTML.php – press release "Indications of the origin of the spin Seebeck effect discovered", 7 Sept. 2015

Petra Giegerich | idw - Informationsdienst Wissenschaft

More articles from Physics and Astronomy:

nachricht Engineering team images tiny quasicrystals as they form
18.08.2017 | Cornell University

nachricht Astrophysicists explain the mysterious behavior of cosmic rays
18.08.2017 | Moscow Institute of Physics and Technology

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>