Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Magnetism loses under pressure

31.01.2008
Scientists have discovered that the magnetic strength of magnetite—the most abundant magnetic mineral on Earth—declines drastically when put under pressure.

Researchers from the Carnegie Institution’s Geophysical Laboratory, together with colleagues at the Advanced Photon Source of Argonne National Laboratory, have found that when magnetite is subjected to pressures between 120,000 and 160,000 times atmospheric pressure its magnetic strength declines by half. They discovered that the change is due to what is called electron spin pairing.

Magnetism comes from unpaired electrons in magnetic materials. The strength of a magnet is a result of the spin of unpaired electrons and how the spins of different electrons are aligned with one another. This research showed that the drop in magnetism was due to a decrease in the number of unpaired electrons.

“Magnetite is found in small quantities in certain bacteria, in brains of some birds and insects, and even in humans,” commented Yang Ding, the study’s lead author with the Carnegie-led High-Pressure Synergetic Consortium. “Early navigators used it to find the magnetic North Pole and birds use it for their navigation. And now it is used in nanotechnology. There is intense scientific interest in its properties. Understanding the behavior of magnetite is difficult because the strong interaction among its electrons complicates its electronic structure and magnetic properties.”

To study the mineral, the researchers developed and applied a novel technique, called X-ray Magnetic Circular Dichroism (XMCD) at the Advanced Photon Source, a high-energy synchrotron facility. The technique uses high-brilliance circularly polarized X-rays to probe the magnetic state of magnetite as a diamond anvil cell subjects a sample to many hundreds of thousands of atmospheres. The researchers combined their experimental results with theoretical calculations by collaborators* to pinpoint why the magnetic strength changes. The study, to be published in February in Physical Review Letters, reveals the electron-spin configuration in the iron sites of the mineral to be the origin of the phenomenon.

This discovery not only shows the profound effects of pressure on magnetism, it also discloses, for the first time, that pressure induced a spin pairing transition that results in changes in the electron mobility and structure.

“The discovery is important,” Ding said. “It advances our understanding of the correlation of magnetism, electron transport, and structural stability in materials with strong electron interactions, like magnetite.”

“It is not surprising to see that a new phenomenon has been trigged by pressure in the oldest magnet. Pressure can directly change electron-electron interactions by squeezing the spacing between them,” said Ho-kwang Mao, the director of the High-Pressure Synergetic Consortium and the High-Pressure Collaborative Access Team. “In the future, the integration of high pressure with novel synchrotron techniques will no doubt lead to more new discoveries.”

Yang Ding | EurekAlert!
Further information:
http://www.aps.anl.gov

More articles from Physics and Astronomy:

nachricht Error-free into the Quantum Computer Age
18.12.2017 | Universität Innsbruck

nachricht Search for planets with Carmenes successful
18.12.2017 | Georg-August-Universität Göttingen

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: Error-free into the Quantum Computer Age

A study carried out by an international team of researchers and published in the journal Physical Review X shows that ion-trap technologies available today are suitable for building large-scale quantum computers. The scientists introduce trapped-ion quantum error correction protocols that detect and correct processing errors.

In order to reach their full potential, today’s quantum computer prototypes have to meet specific criteria: First, they have to be made bigger, which means...

Im Focus: Search for planets with Carmenes successful

German and Spanish researchers plan, build and use modern spectrograph

Since 2016, German and Spanish researchers, among them scientists from the University of Göttingen, have been hunting for exoplanets with the “Carmenes”...

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Error-free into the Quantum Computer Age

18.12.2017 | Physics and Astronomy

Disarray in the brain

18.12.2017 | Studies and Analyses

2 million euros in funding for new MR-compatible electrophysiological brain implants

18.12.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>