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.
The 2014 Sochi Olympics were expected to be a triumphant moment for the U.S. speedskating team—and the squad's sponsor, Under Armour. It's been anything but that. After a strong showing on the World Cup circuit, the team headed to the Games in skinsuits that Under Armour developed and called the fastest speedskating suits in the world.
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.
Only a few elements in the periodic table are inherently magnetic, but scientists have recently discovered that gold, silver, platinum, palladium and other transition metals demonstrate magnetic behavior when formed into nanometer-scale structures. Scientists at the RIKEN Center for Emergent Matter Science have now shown that this nanoscale magnetism in thin films of platinum can be controlled using an externally applied electric field.
Researchers at New York Univ. have developed a method for creating and directing fast moving waves in magnetic fields that have the potential to enhance communication and information processing in computer chips and other consumer products. Their method employs spin waves, which are waves that move in magnetic materials.
Many of the most interesting things in nature, from spectacular lightning strikes to the subtlety of life itself, are transient. To discover the secrets of transient, or far from equilibrium, states, physicists need simple yet appealing laboratory systems. Researchers have managed to create just such a system in the magnetic material known as "spin ice".
Rice Univ. scientists have pioneered a tabletop magnetic pulse generator that does the work of a room-sized machine and more. The device dubbed “RAMBO”, short for Rice Advanced Magnet with Broadband Optics, will allow researchers who visit the university to run spectroscopy-based experiments on materials in pulsed magnetic fields of up to 30 T.
According to new research at the Massachusetts Institute of Technology, graphene, under an extremely powerful magnetic field and at extremely low temperature, can effectively filter electrons according to the direction of their spin. This is something that cannot be done by any conventional electronic system and could render graphene suitable for exotic uses such as quantum computing.
Are electrons truly round? More specifically, is the electron’s charge between its poles uniform? A group at JILA has tackled this difficult question and has developed a method of spinning electric and magnetic fields around trapped molecular ions to measure the tiny electrons. They haven’t yet matched other electric dipole moment measurement techniques, but eventually the new method should surpass them.
A collaboration of physicists and engineers has found a new way to control electron spins not with a magnetic field but with a mechanical oscillator. This demonstration of electron spin resonance that’s “shaken, not stirred” showed that an oscillator can drive the transitions of electron spins within defects commonly found in the crystal lattice of a diamond.
In a new effort to understand magnetism, a group of Hamburg Centre for Ultrafast Imaging researchers created “mimic” magnets by controlling quantum matter waves made of rubidium atoms. Under well-defined conditions made possible with the help of supercomputers, these artificially created magnets can be studied with clarity and then give a fresh perspective on long-standing riddles.
In materials science, electric and magnetic effects have usually been studied separately. There are, however, extraordinary materials called “multiferroics”, in which electric and magnetic excitations are closely linked. Scientists in Austria have now shown in an experiment that magnetic properties and excitations can be influenced by an electric voltage.
A new technique that allows curved surfaces to appear flat to electromagnetic waves has been developed by scientists in England. The discovery could hail a step-change in how antennas are tailored to each platform, which could be useful to a number of industries that rely on high performance antennas for reliable and efficient wireless communications.
Researchers from North Carolina State Univ. have, for the first time, integrated a material called bismuth ferrite (BFO) as a single crystal onto a silicon chip, opening the door to a new generation of multifunctional, smart devices. Integrating the BFO into the silicon substrate as a single crystal makes the BFO more efficient by limiting the amount of electric charge that “leaks” out of the BFO into the substrate.
Cooling systems generally rely on water pumped through pipes to remove unwanted heat. Now, researchers at Massachusetts Institute of Technology and in Australia have found a way of enhancing heat transfer in such systems by using magnetic fields, a method that could prevent hotspots that can lead to system failures. The system could also be applied to cooling everything from electronic devices to advanced fusion reactors, they say.
Scientists in Japan have recently shown that structural control of small magnetic vortex structures called skyrmions could lead to a compact, low-power alternative to conventional magnetic data storage. Skyrmions occur rarely in certain magnetic compounds, but after it was discovered that they can exist near room temperature and can be manipulated with little current, research interest has grown.