(Press-News.org) Normally a material can be either magnetically or electrically polarized, but not both. Now researchers at the Niels Bohr Institute at the University of Copenhagen have studied a material that is simultaneously magnetically and electrically polarizable. This opens up new possibilities, for example, for sensors in technology of the future. The results have been published in the scientific journal, Nature Materials.
Materials that can be both magnetically and electrically polarized and also have additional properties are called multiferroics and were previously discovered by Russian researchers in the 1960s. But the technology to examine the materials did not exist at that time. It is only now, in recent years, that researchers have once again focused on analyzing the properties of such materials. Now you have research facilities that can analyze the materials down to the atomic level.
Surprising test results
"We have studied the rare, naturally occurring iron compound, TbFeO3, using powerful neutron radiation in a magnetic field. The temperature was cooled down to near absolute zero, minus 271 C. We were able to identify that the atoms in the material are arranged in a congruent lattice structure consisting of rows of the heavy metal terbium separated by iron and oxygen atoms. Such lattices are well known, but their magnetic domains are new. Normally, the magnetic domains lie a bit helter-skelter, but here we observed that they lay straight as an arrow with the same distance between them. We were completely stunned when we saw it," explains Kim Lefmann, Associate Professor at the Nano-Science Center, University of Copenhagen.
They were very strange and very beautiful measurements and it is just such a discovery that can awaken the researchers' intense interest. Why does it look like this?
Explaining physics
The experiments were conducted at the neutron research facility Helmholtz-Zentrum in Berlin in collaboration with researchers in Holland, Germany, at ESS in Lund and at Risø/DTU. They would like to get a general understanding of the material and with the help of calculations; and have now arrived at a more precise image of the relationship between the structure of the material and its physical properties.
"What the models are describing is that the terbium walls interact by exchanging waves of spin (magnetism), which is transferred through the magnetic iron lattice. The result is a Yukawa-like force, which is known from nuclear and particle physics. The material exhibits in a sense the same interacting forces that hold the particles together in atomic nuclei," explains Heloisa Bordallo, Associate Professor at the Niels Bohr Institute.
It is precisely this interaction between the transition metal, iron, and the rare element, terbium, that plays an important role in this magneto-electrical material. The terbium's waves of spin cause a significant increase in the electric polarization and the interaction between the ions of the elements creates one of the strongest magneto-electrical effects observed in materials.
"Through these results we found a new pathway to discover and develop new multiferroics", emphasize the researchers in the group. Now it is up to further research to determine whether this new effect could lead to new applications of these materials with the amazing physical properties.
INFORMATION:
Contact:
Kim Lefmann, Associate Professor, Nanophysics, Niels Bohr Institute, University of Copenhagen
+45 3532 0476, +45 2925 0476, lefmann@fys.ku.dk
Heloisa Bordallo, Associate Professor, Nanophysics, Niels Bohr Institute, University of Copenhagen, +45 3532 0425, +45 213 088 29, bordallo@nbi.ku.dk
Niels Bohr Institute: http://www.nbi.ku.dk/english/
Discovery of material with amazing properties
2012-06-25
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
The price tag on a patient-centered medical home
2012-06-25
The patient-centered medical home (PCMH) is a concept at the heart of many health care reform models that aim to both improve the quality of care and reduce wasteful spending. But a new analysis of federally qualified health centers finds that clinics with higher scores as medical homes also had higher per-patient operating costs.
The research, published online in the Journal of the American Medical Association and presented today at the AcademyHealth conference in Orlando, Fla., is the first national study to put a price on these additional costs.
"We're not saying ...
Brain structure helps guide behavior by anticipating changing demands
2012-06-25
Every day the human brain is presented with tasks ranging from the trivial to the complex. How much mental effort and attention are devoted to each task is usually determined in a split second and without conscious awareness. Now a study from Massachusetts General Hospital (MGH) researchers finds that a structure deep within the brain, believed to play an important role in regulating conscious control of goal-directed behavior, helps to optimize behavioral responses by predicting how difficult upcoming tasks will be. The report is receiving advance online publication ...
Blood-brain barrier building blocks forged from human stem cells
2012-06-25
MADISON -- The blood-brain barrier -- the filter that governs what can and cannot come into contact with the mammalian brain -- is a marvel of nature. It effectively separates circulating blood from the fluid that bathes the brain, and it keeps out bacteria, viruses and other agents that could damage it.
But the barrier can be disrupted by disease, stroke and multiple sclerosis, for example, and also is a big challenge for medicine, as it can be difficult or impossible to get therapeutic molecules through the barrier to treat neurological disorders.
Now, however, the ...
Boosting blood system protein complex protects against radiation toxicity
2012-06-25
CINCINNATI - New research in Nature Medicine shows that boosting a protein pathway in the body's blood making system protects mice from otherwise fatal radiation poisoning.
Scientists in the multi-institutional study – posted online by the journal on June 24 – say their findings open the potential for new treatments against radiation toxicity during cancer treatment or environmental exposures – such as in a nuclear explosion or accident.
By identifying a target-specific intervention to protect the hematopoietic system against radiation toxicity, the study addresses ...
Gene mutations cause massive brain asymmetry
2012-06-25
Hemimegalencephaly is a rare but dramatic condition in which the brain grows asymmetrically, with one hemisphere becoming massively enlarged. Though frequently diagnosed in children with severe epilepsy, the cause of hemimegalencephaly is unknown and current treatment is radical: surgical removal of some or all of the diseased half of the brain.
In a paper published in the June 24, 2012 online issue of Nature Genetics, a team of doctors and scientists, led by researchers at the University of California, San Diego School of Medicine and the Howard Hughes Medical Institute, ...
Climate change and the South Asian summer monsoon
2012-06-25
The vagaries of South Asian summer monsoon rainfall impact the lives of more than one billion people. A review in Nature Climate Change (June 24 online issue) of over 100 recent research articles concludes that with continuing rise in CO2 and global warming, the region can expect generally more rainfall, due to the expected increase in atmospheric moisture, as well as more variability in rainfall.
In spite of the rise in atmospheric CO2 concentration of about 70 parts per million by volume and in global temperatures of about 0.50°C over the last 6 decades, the All India ...
Faster, cheaper gas and liquid separation using custom designed and built mesoscopic structures
2012-06-25
Kyoto, Japan -- In what may prove to be a significant boon for industry, separating mixtures of liquids or gasses has just become considerably easier.
Using a new process they describe as "reverse fossilization," scientists at Kyoto University's WPI Institute for Integrated Cell-Material Sciences (iCeMS) have succeeded in creating custom designed porous substances capable of low cost, high efficiency separation.
The process takes place in the mesoscopic realm, between the nano- and the macroscopic, beginning with the creation of a shaped mineral template, in this case ...
Significant sea-level rise in a 2-degree warming world
2012-06-25
The study is the first to give a comprehensive projection for this long perspective, based on observed sea-level rise over the past millennium, as well as on scenarios for future greenhouse-gas emissions.
"Sea-level rise is a hard to quantify, yet critical risk of climate change," says Michiel Schaeffer of Climate Analytics and Wageningen University, lead author of the study. "Due to the long time it takes for the world's ice and water masses to react to global warming, our emissions today determine sea levels for centuries to come."
Limiting global warming could considerably ...
Higher medical home performance rating of community health centers linked with higher operating cost
2012-06-25
CHICAGO – Federally funded community health centers with higher patient-centered medical home ratings on measures such as quality improvement had higher operating costs, according to a study appearing in JAMA. This study is being published early online to coincide with its presentation at the Annual Research Meeting of AcademyHealth.
"The patient-centered medical home (PCMH) is a model of care characterized by comprehensive primary care, quality improvement, care management, and enhanced access in a patient-centered environment. The PCMH is intuitively appealing and has ...
Better looking birds have more help at home with their chicks
2012-06-25
In choosing a mate both males and females rely on visual cues to determine which potential partner will supply the best genes, best nesting site, best territory, and best parenting skills. New research published in BioMed Central's open access journal Frontiers in Zoology shows that male blue tits' (Cyanistes caeruleus) parental behavior is determined by female ornamentation (ultraviolet coloration of the crown), as predicted by the differential allocation hypothesis (DAH).
DAH makes the assumption that aesthetic traits indicate quality and arises from the needs of a ...