Scientists solve riddle of strangely behaving magnetic material
June 21, 2013 Materials scientists at the U.S. Department of Energy's (DOE) Ames Laboratory have found an accurate way to explain the magnetic properties of a compound that has mystified the scientific community for decades.
The compound of lanthanum, cobalt and oxygen (LaCoO3) has been a puzzle for over 50 years, due to its strange behavior. While most materials tend to lose magnetism at higher temperatures, pure LaCoO3 is a non-magnetic semiconductor at low temperatures, but as the temperature is raised, it becomes magnetic. With the addition of strontium on the La sites the magnetic properties become even more prominent until, at 18 percent strontium, the compound becomes metallic and ferromagnetic, like iron.
"They knew that we could calculate x-ray absorption and magnetic dichroism, so we started doing that. It is a case where we fell into doing what we thought was a routine calculation, and it turned out we discovered a totally different explanation," said Harmon. "We found we could explain pretty much everything in really nice detail, but without explicitly invoking that local model," said Harmon.
The scientists found that a small rhombohedral distortion of the LaCoO3 lattice structure, which had largely been ignored, was key.
"We found that the total electronic energy of the lattice depends sensitively on that distortion," explained Harmon. "If the distortion becomes smaller (the crystal moves closer to becoming cubic), the magnetic state of the crystal switches from non-magnetic to a state with 1.3 Bohr magnetons per Co atom."
Ames Laboratory scientists Bruce Harmon and Yongbin Lee partnered with the researchers at the Argonne National Laboratory and the University of California, Santa Cruz to publish a paper in Physical Review Letters, "Evolution of Magnetic Oxygen States in Sr-Doped LaCO3."
This new understanding may help the further development of these materials, which are easily reduced to nanoparticles; these are finding use in catalytic oxidation and reduction reactions associated with regulation of noxious emissions from motor vehicles.
The research is supported by the U.S. Department of Energy Office of Science through the Ames Laboratory.
Welcome to SUV System Ltd!
SUV System Ltd is ISO 90012008 Certified electronics distributor with 10 years of experiences.
We have built up long term business relationship with about many companies which are stockers and authorized agents. we have a steady and reliable supply to meet customer's demands to the greatest extent .Confidently, we are able to lower your cost and support your business with our years of professional service.
SUV System Ltd is Electronic Components Distributor Supplies,Find Quality Electronic Components Supplies Products IC(Integrated Circuits),Connectors,Capacitor,Resistors,Diodes,Transistors,LED at Suvsystem.com. Sourcing Other Energy, Environment, Excess Inventory Products from Manufacturers and Suppliers at Suvsystem.com
Electronic Components distributor:http://www.suvsystem.com
Connectors Distributor:http://www.suvsystem.com/l/Connectors-1.html
IC Distributor:http://www.suvsystem.com/l/IC(Integrated-Circuits)-1.html
LED Distributor:http://www.suvsystem.com/l/LED-1.html
Capacitor Distributor:http://www.suvsystem.com/l/Capacitor-1.html
Transistor Distributor:http://www.suvsystem.com/l/Transistors-1.html
Resistor Distributor:http://www.suvsystem.com/l/Resistors-1.html
Diode Distributor:http://www.suvsystem.com/l/Diodes-1.html
SUV System Ltd insists on the managing faith ofsincereness,speciality,foresight, win-win,so we build up stable-relationship customers located all over the world, including the States, Europe, Argentina, UAE, Malaysia, Australia,and India etc
we are focus on the following fields,and hope we can help you.
BFC246213002 BFC246212702 BFC246212402 BFC246212202 BFC246212002 BFC246211802 BFC246211602 BFC246211502 BFC246211302 BFC246211202 BFC246203302 BFC246203002 BFC246202702 BFC246244302 BFC246243902 BFC246243602 BFC246243302 BFC246243002 BFC246242702 BFC246242402 BFC246242203 BFC246242202 BFC246242003 BFC246242002 BFC246241803 BFC246241802 BFC246241603 BFC246241602 BFC246241503 BFC246241502 BFC246241303 BFC246241302 BFC246241203 BFC246241202 BFC246241103 BFC246241003 BFC246239102 BFC246238202 BFC246237502 BFC246236802
http://www.suvsystem.com/a/3119.aspx
没有评论:
发表评论