Featured Research

from universities, journals, and other organizations

Novel magnetism discovered in iridium compound CuIr2S4

Date:
March 12, 2014
Source:
National Institute for Materials Science
Summary:
Researchers have discovered the first experimental evidence showing the importance of spin-orbit interactions that were previously overlooked in CuIr2S4. It opens up a new area of research with respect to spin-orbit interactions in transition metals.

Researchers have discovered the first experimental evidence showing the importance of spin-orbit interactions that were previously overlooked in CuIr2S4. It opens up a new area of research with respect to spin-orbit interactions in transition metals.

The research unit that includes Associate Professor Kenji Kojima and Professor Ryosuke Kadono of the Institute of Materials Structure Science, KEK, investigated the magnetic properties of the iridium compound Cu1-xZnxIr2S4 using the muon spin rotation method. This was undertaken in collaboration with Principal Researcher Hiroyuki Suzuki and Unit Director Hideaki Kitazawa of the Advanced Key Technologies Division, NIMS.

The researchers found that the host material with zero zinc concentration, (x = 0) CuIr2S4, is not nonmagnetic as previously believed, but shows novel magnetism below ~ 100 K, and that this magnetism state rapidly disappears when slight amounts of zinc (x ~ 0.01) are substituted.

The iridium compound that was investigated, CuIr2S4, comprises a spinel structure and is metallic at room temperature, but it becomes an insulator below 230 K.

Previous structural analysis has showed that, upon becoming an insulator, iridium separates into tetravalent and trivalent ions, each forming octamers. Moreover, one type of bond between tetravalent octamer iridium (green, blue, and red lines in Fig. 1) becomes shorter than the others, and pairs of iridium at both sides of these bonds form four independent pairs.

Such structural changes have been confirmed in samples synthesized by the NIMS group through structural analysis using synchrotron X-rays from the KEK Photon Factory.

Research into the magnetic properties of the iridium compound CuIr2S4 using muon spin rotation at J-PARC and TRIUMF (Canada) found an inhomogeneous internal magnetic field below ~ 100 K that is considered to be induced by the magnetic moments of iridium.

Spin glass is one class of magnetic materials that illustrates such magnetism. Previously, CuIr2S4 was believed to have pairs of electron spin when tetrahedra distort in one direction at low temperature, and that this spin singlet state removes magnetic frustration; however, the results presented here reject this hypothesis.

The team also found that substitution of copper with zinc (Cu1-xZnxIr2S4) results in a sudden loss of magnetism in iridium at x ~ 0.01 (1%). Superconductivity is known to appear at x greater than ~ 0.25 in this material, so the relation between magnetism found in this research and superconductivity attracts much interest. As a result, CuIr2S4 is expected to provide a new line of research, different from Sr2IrO4, that further considers the effect of spin-orbit interaction in transition metals.

The discovery in this research is the first experimental evidence concerning the importance of spin-orbit interactions that were previously overlooked in CuIr2S4 and also shows that this material opens up a new area of research with respect to spin-orbit interactions in transition metals. The results were published in the online version of the journal Physical Review Letters.


Story Source:

The above story is based on materials provided by National Institute for Materials Science. Note: Materials may be edited for content and length.


Cite This Page:

National Institute for Materials Science. "Novel magnetism discovered in iridium compound CuIr2S4." ScienceDaily. ScienceDaily, 12 March 2014. <www.sciencedaily.com/releases/2014/03/140312103040.htm>.
National Institute for Materials Science. (2014, March 12). Novel magnetism discovered in iridium compound CuIr2S4. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/2014/03/140312103040.htm
National Institute for Materials Science. "Novel magnetism discovered in iridium compound CuIr2S4." ScienceDaily. www.sciencedaily.com/releases/2014/03/140312103040.htm (accessed July 23, 2014).

Share This




More Matter & Energy News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Government Approves East Coast Oil Exploration

Government Approves East Coast Oil Exploration

AP (July 18, 2014) The Obama administration approved the use of sonic cannons to discover deposits under the ocean floor by shooting sound waves 100 times louder than a jet engine through waters shared by endangered whales and turtles. (July 18) Video provided by AP
Powered by NewsLook.com
Sunken German U-Boat Clearly Visible For First Time

Sunken German U-Boat Clearly Visible For First Time

Newsy (July 18, 2014) The wreckage of the German submarine U-166 has become clearly visible for the first time since it was discovered in 2001. Video provided by Newsy
Powered by NewsLook.com
Obama: U.S. Must Have "smartest Airports, Best Power Grid"

Obama: U.S. Must Have "smartest Airports, Best Power Grid"

Reuters - US Online Video (July 17, 2014) President Barak Obama stopped by at a lunch counter in Delaware before making remarks about boosting the nation's infrastructure. Mana Rabiee reports. Video provided by Reuters
Powered by NewsLook.com
Crude Oil Prices Bounce Back After Falling Below $100 a Barrel

Crude Oil Prices Bounce Back After Falling Below $100 a Barrel

TheStreet (July 16, 2014) Oil Futures are bouncing back after tumbling below $100 a barrel for the first time since May yesterday. Jeff Grossman is the president of BRG Brokerage and trades at the NYMEX. Grossman tells TheStreet the Middle East is always a concern for oil traders. Oil prices were pushed down in recent weeks on Libya increasing its production. Supply disruptions in Iraq fading also contributed to prices falling. News from China's economic front showing a growth for the second quarter also calmed fears on its slowdown. Jeff Grossman talks to TheStreet's Susannah Lee on this and more on the Energy Department's Energy Information Administration (EIA) report. Video provided by TheStreet
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins