The magnets cluttering the face of your refrigerator may one day be used as cooling agents, according to a new theory. The theory describes the motion of magnons. In addition to magnetic moments, magnons also conduct heat; from their equations, the researchers found that when exposed to a magnetic field gradient, magnons may be driven to move from one end of a magnet to another, carrying heat with them and producing a cooling effect.
Using a new type of large-scale magnet conductor, scientists in Japan have recently achieved an electrical current of 100,000 A, a world record. The conductor, which was built using yttrium-based high-temperature superconducting tapes for high mechanical strength, is a prototype for using in a future fusion reactor.
Vibrate a solution of rod-shaped metal nanoparticles in water with ultrasound and they'll spin around their long axes like tiny drill bits. Why? No one yet knows exactly. But researchers at the NIST have clocked their speed, and it's fast. At up to 150,000 revolutions per minute, these nanomotors rotate 10 times faster than any nanoscale object submerged in liquid ever reported.
Most current methods of identifying intracellular information result in the death of the individual cells, making it impossible to continue to gain information and assess change over time. Using magnetized carbon nanotubes, scientists in Texas have devised a new method for extracting molecules from live cells without disrupting cell development.
Perovskites continue to entice materials scientists with their mix of conductivity, ferroelectricity, ferromagnetism, and catalytic activity. In recent years, scientists realized that they could vastly improve the properties of perovskites by assembling them into thin films, but nobody knew the reason why. But studying the chemistry layer-by-layer, experts working with x-ray beamline at Argonne National Laboratory are getting close.
Scientists at the Univ. of California, Riverside have constructed liquid crystals with optical properties that can be instantly and reversibly controlled by an external magnetic field. Unlike conventional liquid crystals, which rotate and align themselves when an electric field is applied, the new crystals are essentially a liquid dispersion of magnetic nanorods.
An international research team led by scientists in Barcelona has developed a material which guides and transports a magnetic field from one location to the other, similar to how an optical fiber transports light or a hose transports water. The magnetic hose consists of a ferromagnetic cylinder covered by a superconductor material, a surprisingly simple design made possible by complicated theoretical calculations and experimentation.
A breakthrough has been made in identifying the origin of superconductivity in high-temperature superconductors, which has puzzled researchers for the past three decades. Researchers in the U.K. have found that ripples of electrons, known as charge density waves or charge order, create twisted ‘pockets’ of electrons in these materials, from which superconductivity emerges.
Researchers in California have created a nanoscale magnetic component for computer memory chips that could significantly improve their energy efficiency and scalability. The design brings spintronics one step closer to being used in computer systems by adopting a new strategy called “spin-orbit torque” that eliminates the need for a magnetic field for switching processes.
Nanoscale magnetic swirls known as skyrmions can form in certain materials such as thin magnetic films. These tiny vortices pack into dense lattices that are more stable than conventional magnetic domains and can be manipulated with minimal electrical power. Researchers in Japan have now made major progress in understanding this phenomenon by conducting the first 3-D analysis of skyrmion lattices using an electron holography microscope.
As part of a series of experiments designed to resolve one of the deepest mysteries of physics today, researchers have made the most precise ever direct measurement of the magnetic moment of a proton. The measurement, based on spectroscopy of a single particle in a Penning trap, was completed at a fractional precision of 3 parts per billion, improving the 42-year-old "fundamental constant" by a factor of three.
New analysis of ancient Jian wares reveals the distinctive pottery contains an unexpected and highly unusual form of iron oxide. This rare compound, called epsilon-phase iron oxide, was only recently discovered and characterized by scientists and so far has been extremely difficult to create with modern techniques.
A research collaboration has combined several experimental and computational methods to measure, for the first time, the energy needed to change the magnetic anisotropy of a single cobalt atom. Their methodology included the use of inelastic electron tunneling spectroscopy to determine a cobalt atom’s “stubbornness”, or preference toward specific magnetic direction.
Scientists at Brookhaven National Laboratory are seeking ways to synchronize the magnetic spins in nanoscale devices to build tiny yet more powerful signal-generating or receiving antennas and other electronics. Their latest work shows that stacked nanoscale magnetic vortices separated by a thin layer of copper can be driven to operate in unison, potentially producing a powerful signal that could be put to work in new electronics.
Traditionally, scientists discover new materials, and then probe them to understand their properties. Theoretical materials physicist Craig Fennie does it in reverse. He creates new materials by employing a "first principles" approach based on quantum mechanics, in which he builds materials atom by atom, starting with mathematical models, in order to gain the needed physical properties.
Using a new trick, researchers in Germany have been able to induce synchronous motion of the domain walls in a ferromagnetic nanowire. This is an important breakthrough for controlled movement of domain walls that allows permanent data to be stored using nanomagnets. The advance involved applying a pulsed magnetic field that was perpendicular to the plane of the domain walls.
Interest in oxide-based semiconductor electronics has exploded in recent years, fueled largely by the ability to grow atomically precise layers of various oxide materials. One of the most important materials in this burgeoning field is strontium titanate, a nominally nonmagnetic wide-bandgap semiconductor, and researchers have found a way to magnetize this material using light, an effect that persists for hours at a time.
Phosphorus can be found in fertilizers, drinks and detergents, and it accumulates in waterways, polluting them. For this reason, researchers in Germany have developed a new platform for recovering this valuable but harmful element from water. They have attached bonding sites for phosphorus to particles so that they fish the phosphate anions out of the water and carry them “piggyback”. The particles can be applied using a magnet.
Inspired by the space physics behind solar flares and the aurora, a team of researchers from the Univ. of Michigan and Princeton Univ. has uncovered a new kind of magnetic behavior that could help make nuclear fusion reactions easier to start.
A new mechanism of controlling magnetic states by electric currents has been discovered by an international team of researchers who have exploited a quantum phenomenon to control magnetic states with electrical currents. The research hinges on a quantum geometrical phase, called the Berry phase, that exists in the momentum space of electronic band structures in specific materials.
Current technologies for writing, storing, and reading information are either charge-based or spin-based. The downside is that weak perturbations such as impurities or radiation can lead to uncontrolled charge redistributions and, as a consequence, to data loss. Researchers in Europe have predicted and discovered a new physical phenomenon that allows them to manipulate the state of a magnet by electric signals and eliminate this loss.
According to recent findings by an international team of computer engineers, optical data storage does not require expensive magnetic materials because synthetic alternatives work just as well. The team’s discovery that synthetic ferrimagnets can be switched optically brings a much cheaper method for storing data using light a step closer.
A Chinese-U.S. research team is exploring the use of metamaterials to create devices that manipulate sound in versatile and unprecedented ways. In a recently published paper, the team reports a simple design for a device, called an acoustic field rotator, which can twist wave fronts inside it so that they appear to be propagating from another direction.
There is a big effort in industry to produce electrical devices with more and faster memory and logic. Magnetic memory elements, such as in a hard drive, and in the future in what is called MRAM (magnetic random access memory), use electrical currents to encode information. However, the heat which is generated is a significant problem, since it limits the density of devices and hence the performance of computer chips.
New research at the Univ. of Arkansas reveals a novel magnetoelectric effect that makes it possible to control magnetism with an electric field. The novel mechanism may provide a new route for using multiferroic materials for the application of RAM (random access memories) in computers and other devices, such as printers.