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.
After more than 40 years of intense research, experimental physicists still seek to explore the rich behavior of electrons confined to a 2-D crystalline structure exposed to large magnetic fields. Now a team in Europe has developed a new experimental method to simulate these systems using a crystal made of neutral atoms and laser light.
A new study set out to use numerical simulations to validate previous theoretical predictions describing materials exhibiting so-called antiferromagneting characteristics. A recently discovered theory shows that the ordering temperature depends on two factors—namely the spin-wave velocity and the staggered magnetization. The simulations match these theoretical predictions.
Researchers have recently provided the first evidence ever that it is possible to generate a magnetic field by using heat instead of electricity. The phenomenon is referred to as the Magnetic Seebeck effect or “thermomagnetism”.
Using low-frequency laser pulses, a team of researchers has carried out the first measurements that reveal the detailed characteristics of a unique kind of magnetism found in a mineral called herbertsmithite. In this material, the magnetic elements constantly fluctuate, leading to an exotic state of fluid magnetism called a “quantum spin liquid.”
Just like people, materials can sometimes exhibit “multiple personalities.” This kind of unusual behavior in a certain class of materials has compelled researchers at Argonne National Laboratory to take a closer look at the precise mechanisms that govern the relationships between superconductivity and magnetism.
Researchers at North Carolina State Univ. have created a new compound, strontium tin oxide (Sr3SnO) that can be integrated into silicon chips and is a dilute magnetic semiconductor, meaning that it could be used to make “spintronic” devices, which rely on magnetic force to operate, rather than electrical currents.
Though nanosatellites already borrow several components, including cameras and radios, from terrestrial gadgets, propulsion systems have to be built from scratch. Researchers are working on electrospray ionic liquid “rockets”, but the microscopic needles they require are difficult and tedious to make. A researcher has found a way to let nature do the work, simplifying the fabrication process.
Researchers in Israel have developed a simple magnetization progress that depends on electron spin to eliminate the need for permanent magnets in memory devices. The new technique, called magnetless spin memory (MSM), drives a current through chiral material and selectively transfers electrons to magnetize nanomagnetic layers or nanoparticles.