November 2017

Researchers from the University of Nebraska-Lincoln designed a spintronics transistor that is based on graphene. The researchers say that such a device could be highly efficient, run at room temperature (and above) and feature a nonvolatile on-off current ratio and electrically controllable spin polarization.

The device is based on the discovery that an external voltage can be used to control the magnetic properties of few-layer graphene interfaced with chromium oxide. This is a theoretical research at this stage but the new device structure is expected to feature a large electrically controllable spin current.

Researchers from Japan and China have discovered the exotic dynamics of frustrated magnetic skyrmions - which are different from that of magnetic skyrmions in common ferromagnetic materials. Magnetic skyrmions are very interesting for several spintronic applications, including magnetic memory and logic computing devices.

In conventional ferromagnetic materials, the helicity (degree of freedom) of a skyrmion cannot be effectively controlled, but the researchers found that in frustrated magnetic materials it is possible to control the skyrmion helicity by utilizing the helicity locking-unlocking transition of the material. The researcher further conclude that one can use frustrated skyrmions as a binary memory utilizing two stable Bloch-type states, where the helicity can be switched by applying current.

Researchers from Spain's ICN2 institute have performed numerical simulations for spin relaxation in graphene/TMDC heterostructures, and found that these structure feature a spin lifetime anisotropy that is orders of magnitude larger than anything observed in 2D materials - and in fact these results point to a qualitatively new regime of spin relaxation.

Spin relaxation lifetime means that time it takes for the spin of electrons in a spin current to lose their spin (return to the natural random disordered state). A long lifetime is very important for spintronics devices. This new study reveals that the rate at which spins relax in graphene/TMDC systems depends strongly on whether they are pointing in or out of the graphene plane, with out-of-plane spins lasting tens or hundreds of times longer than in-plane spins.

Researchers from the University of Cambridge and TU Eindhoven have created a nanoscale magnetic circuit capable of moving information through three-dimensional space. This so-called 3D nanoprinting, combined with traditional methods enables functional circuits that can process information, which could lead to future spintronics device development.

To create these 3D nanomagnets, the researchers used an electron microscope along with a gas injector to 3-D print a suspended scaffold on a traditional 2-D Silicon substrate. After 3-D nano-printing, magnetic material is deposited over the whole ensemble to allow information transport.

Electron 'holes' in semiconductors are very attractive for future spintronics devices due to their unique spin properties, but until now researchers did not have a good understanding of these spin properties. Researchers from Australia's UNSW have classified the spin-orbit effects of holes confined to one dimension for the first time.

The researchers started out by trying to explain a 2006 experimental result, that showed that in on-dimensional quantum wires, spin-splitting was extremely sensitive to the direction of the magnetic field, unlike electrons which are insensitive to the field direction. In the recent study, the researchers identified a new spin-orbit interaction factor caused by the holes’ confinement to one dimension, and found that this new factor explained the 2006 experimental result.

Researchers from the University of York and Roma Tre University developed a method to build ultra-low-power transistors using composite materials based on single layers of graphene and transition metal dichalcogenides (TMDC). These materials can be used to achieve an electrical control over electron spin.

The teams explained “we found this can be achieved with little effort when 2D graphene is paired with certain semiconducting layered materials. Our calculations show that the application of small voltages across the graphene layer induces a net polarization of conduction spins".