When "frustrated" by their arrangement, magnetic atoms surrender their individuality, stop competing with their neighbors and then practice a group version of spin control—acting collectively to achieve local magnetic order—according to scientists from the Commerce Departments National Institute of Standards and Technology, Johns Hopkins University and Rutgers University writing in the Aug. 22, 2002, issue of the journal Nature.
Chill! Atoms in zincochromite, a "geometrically frustrated magnet," resolve their frustration through group spin control. Neighboring tetraheda (solids with four triangular faces) contribute a side each to create hexagonal (six-sided) spin clusters. A hexagon bunches the spins of magnetic atoms-one at each corner-into a single "spin director" (arrows). The composite behavior achieves local magnetic order.
The unexpected composite behavior detected in experiments done at the NIST Center for Neutron Research (NCNR) accounts for the range of surprising—and, heretofore, unexplainable—properties of so-called geometrically frustrated magnets, the subject of intensifying research efforts that may lead to new types of matter. The finding also may shed light on natural clustering processes including the assembly of quarks and other minuscule components into atoms, the folding of proteins and the clumping of stars in galaxies, the scientists say.
These and other important phenomena—including high-temperature superconductivity—suggest that there are "higher-order organizing principles that are intrinsic to nature," explains lead author Seung-Hun Lee, NCNR staff physicist.
Mark Bello | EurekAlert!
Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences
Nano-kirigami: 'Paper-cut' provides model for 3D intelligent nanofabrication
16.07.2018 | Chinese Academy of Sciences Headquarters
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
16.07.2018 | Physics and Astronomy
16.07.2018 | Life Sciences
16.07.2018 | Earth Sciences