Spintronics-Info: the spintronics experts

The International Institute of Physics in Brazil recently uploaded this interesting talk by Ahmet Avsar, from the EPFL, who discusses spintronics in 2D materials (such as graphene):

This talk was given as part of the IIP's 2D Materials: From Fundamentals to Spintronics workshop which took place in early October.

An international team of researchers from France and Sweden designed a new concept of an energy harvesting engine based on spintronics and quantum thermodynamics. The basic idea is to use electron spin to harvest thermal fluctuations at room temperature.

The researchers make use of the fact that paramagnetic centers, or atom-level magnets, fluctuate their spin orientation due to heat. In the so called spin-engine, the a spontaneous bias voltage V appears between the electrodes, and thus a spontaneous current flows once the electrical circuit is closed.

There are still many challenges to create such devices (the team made some initial experiments) - but the researchers say that this concept could create chips that continuously produce electrical power with a power density that is 3x greater than raw solar irradiation on Earth.

Researchers from the University of Groningen created curved spin transport channels. The researchers discovered that this new geometry makes it possible to independently tune charge and spin currents.

Most spintronics devices to date were made from flat surfaces, and this research focused on spin currents behaviors in curved channels. The scientists say that the new research enables the efficient integration of spin injectors and detectors or spin transistors into modern 3D circuitry.

Researchers from Japan's National Institute for Materials Science (NIMS) have managed to introduce a quantum well structure into a conventional magnetic tunnel junction (MTJ). The researchers say that the QW structure can enhance the tunneling magnetoresistance (TMR) ratio by spin-dependent resonant tunnel (SDRT) effect, with a value of 1.5 times comparing with no SDRT case, at room temperature.

The researchers tell us that the key point of the QW formation is the band mismatch between Cr and Fe for majority band, and the mismatch-free Fe/MgAl₂O₄ interface. The finding is not just useful for enhancement of TMR ratio, it also provides a benefit that the TMR ratio could be kept almost constant in a wide bias voltage range of from -1V to 0.5V.

Researchers from the University of Groningen developed a two-dimensional spin transistor, in which spin currents were generated by an electric current through graphene. The device also include a monolayer transition metal dichalcogenide (TMD) that is placed on the graphene to induce charge-to-spin conversion.

Graphene is an excellent spin transporter, but spin-orbit coupling is required to create or manipulate spins. The interaction is weak in the graphene carbon atoms, but now the researchers have shown that adding the TMD layer increases the spin-orbit coupling.

The Sofja Kovalevskaja Award, Germany's most highly-endowned research award for early-research scientists, went this year to Dr Angelo Di Bernardo from Cambridge University. Dr. Angelo was awarded with 1.65 million Euros and will move to the University of Konstant in which he will establish a research hub in the field of superconducting spintronics.

Dr. Angelo's project that won the award is dealing with superconducting spintronics with oxides and 2D materials.

Researchers from Spain's ICN2, in collaboration with Imec and K.U. Leuven have developed a modified graphene-based nanodevice fabrication technique that can increase the spin lifetime and relaxation length by up to three times.

The researchers used CVD-made graphene grown on a platinum foil. By optimizing several standard processes, the researchers managed to reduce the impurity level of the graphene.