Featured Research

from universities, journals, and other organizations

A New Understanding Of Crystal Structure Of Actinide Metals

Date:
June 7, 2007
Source:
DOE/Lawrence Livermore National Laboratory
Summary:
Researchers have a better understanding of how the crystal structure of some metals becomes stable through magnetism. Magnetic stabilization of the crystal structures of metals is rare. In some metals, such as manganese, iron, and cobalt, the magnetic interaction energy is large enough to influence the crystal structure.

Researchers from of Lawrence Livermore and Oak Ridge national laboratories and Daresbury Laboratory in the United Kingdom, probed the electronic and magnetic structure of Cm by using electron energy-loss spectroscopy in a transmission electron microscope, electron atomic calculations and density functional theory.
Credit: Image courtesy of DOE/Lawrence Livermore National Laboratory

Researchers have a better understanding of how the crystal structure of some metals becomes stable through magnetism.

Related Articles


Magnetic stabilization of the crystal structures of metals is rare. In some metals, such as manganese, iron, and cobalt, the magnetic interaction energy is large enough to influence the crystal structure.

However, recent research shows that magnetically stabilized crystal structures also include the heavy actinide element, curium (Cm). In a diamond-anvil cell study, Cm was pressurized up to one million atmospheres of pressure, which caused the metal to undergo transformations between five different crystal phases.

But a new study by Livermore scientists goes one step further. The team, made up researchers from of Lawrence Livermore and Oak Ridge national laboratories and Daresbury Laboratory in the United Kingdom, probed the electronic and magnetic structure of Cm by using electron energy-loss spectroscopy (EELS) in a transmission electron microscope (TEM), electron atomic calculations and density functional theory (DFT).

To date absorption-type experiments have not been performed on americium (Am) or Cm.

“Our results for curium go a long way in teaching us a general understanding of how this mechanism occurs,” said Kevin Moore, the LLNL lead author of the research paper that appears in the June 8 issue of the journal Physical Review Letters.  Other Livermore researchers include Mark Wall, Adam Schwartz and Per Sφderlind as well as Gerrit van der Laan from Daresbury and Richard Haire from Oak Ridge.

The Hund’s rule coupling is the key to producing the large spin polarization that dictates the newly found crystal structure of Cm under pressure.

Hund’s rule of maximum spin multiplicity is a principle of atomic chemistry, which assumes that a greater total spin state usually makes the resulting atom more stable, most commonly exhibited in a lower energy state, because it forces the unpaired electrons to reside in different spatial orbitals. By staying out of each others way, the electrons lower their total energy.

“This gives us great insight into the valence state and electron coupling mechanisms of 5f electrons in plutonium and americium, two metals that are significant to nuclear reactors,” Moore said. “Our data will help us refine our theoretically predictive codes for these metals to give us a better understanding of the physical properties of the metals and how they will behave under extreme conditions.”

The Livermore research also helps fill a gap in a recent Nature paper (446, page 513, 2007) from Rutgers University that had a missing data point in a table. The LLNL americium and curium data fill the blank space in the table.

“The two papers (PRL and Nature) greatly further our understanding of the middle actinide metals – plutonium, americium and curium.”


Story Source:

The above story is based on materials provided by DOE/Lawrence Livermore National Laboratory. Note: Materials may be edited for content and length.


Cite This Page:

DOE/Lawrence Livermore National Laboratory. "A New Understanding Of Crystal Structure Of Actinide Metals." ScienceDaily. ScienceDaily, 7 June 2007. <www.sciencedaily.com/releases/2007/06/070606113438.htm>.
DOE/Lawrence Livermore National Laboratory. (2007, June 7). A New Understanding Of Crystal Structure Of Actinide Metals. ScienceDaily. Retrieved April 19, 2015 from www.sciencedaily.com/releases/2007/06/070606113438.htm
DOE/Lawrence Livermore National Laboratory. "A New Understanding Of Crystal Structure Of Actinide Metals." ScienceDaily. www.sciencedaily.com/releases/2007/06/070606113438.htm (accessed April 19, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Sunday, April 19, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

At Least 15 Injured in a California Natural Gas Pipeline Explosion

At Least 15 Injured in a California Natural Gas Pipeline Explosion

Reuters - US Online Video (Apr. 18, 2015) — At least 15 injred after natural gas transmission line ruptures in Fresno, California. Julie Noce reports. Video provided by Reuters
Powered by NewsLook.com
NASA Electric Rover Goes for a Spin

NASA Electric Rover Goes for a Spin

Reuters - Innovations Video Online (Apr. 17, 2015) — NASA&apos;s prototype electric buggy could influence future space rovers and conventional cars. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com
Scientists Create Self-Powering Camera

Scientists Create Self-Powering Camera

Reuters - Innovations Video Online (Apr. 17, 2015) — American scientists build a self-powering camera that captures images without using an external power source, allowing it to operate indefinitely in a well-lit environment. Elly Park reports. Video provided by Reuters
Powered by NewsLook.com
The State Of Virtual Reality

The State Of Virtual Reality

Newsy (Apr. 17, 2015) — Virtual Reality is still a young industry. What’s on offer and what should we expect from our immersive new future? Video provided by Newsy
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:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

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