Spintronics-Info: the spintronics experts

Researchers from Shinshu University, the Chinese University of Hong Kong, the University of Tokyo, Tsinghua University, Kyoto University and Nanyang Technological University have experimentally demonstrated a breakthrough in manipulation of skyrmions using only electric field.

The team, led by Professor Xiaoxi Liu of Shinshu University, designed and fabricated magnetic multilayer films in the form of racetracks where the thickness of the films had a slope. They demonstrated that many skyrmion bubbles can be created and directionally displaced about 10 micrometres by applying a voltage as low as 9 volt in a repeatable manner. They also found that the domain wall displacement and velocity induced by the variation of electric field are proportional to the absolute value of voltage.

Researchers from the University of Tokyo developed a method to partially switch between specific magnetic states at Thz frequencies. The researchers used short high-frequency pulses of terahertz radiation to flip the electron spins in ferromagnetic manganese arsenide (MnAs).

Such techniques have been attempted before, but the magnitude change in the magnetization of the MnAs was too small - but in this current research a 20% change was achieved. Such a technique could be used in the future to create Thz spintronics devices - one that operate at a much faster rate compared to today's Ghz electronics devices.

Researchers from Sultan Qaboos University in Oman, Johannes Gutenberg-Universität Mainz in Germany and Nanyang Technological University in Singapore have experimentally demonstrated a breakthrough in one of the major problems blocking the adoption of magnetic domain wall memory.

When recording each fresh bit of information onto a racetrack, there is considerable uncertainty about where each magnetic domain starts and ends, and an incorrectly-written bit can easily lead to the corruption of bits. The team, led by Professor Rachid Sbiaa of Sultan Qaboos University, devised a method to overcome this difficulty by using a staggered nanowire (see figure below).

Researchers from Japan's Tohoku University have developed a nonvolatile microcontroller unit (MCU) which achieves both high performance and ultra-low power by utilizing spintronics-based VLSI design technology and STT-MRAM memory.

The researchers used several new techniques to create an efficient and fast device. Each module's power supply is controlled independently, which eliminates wasteful power consumption, while a memory controller and a reconfigurable accelerator module are used to relax data transfer bottlenecks. These new techniques enabled the researchers to achieve ultra-lower power consumptioN (47.14 uW) at 200Mhz.

Researchers from the Helmholtz-Zentrum Berlin für Materialien und Energie Institute demonstrate how it is possible to induce a magnetic order on a small region of a material by using a small electric field, instead of commonly used magnetic field.

Te researchers used a wedge-shaped polycrystalline iron thin film deposited on top of a BaTiO₃ substrate (a well-known ferroelectric and ferroelastic material). Given their small size, the magnetic moments of the iron nanograins are disordered with respect to each other, this state is known as superparamagnetism.

Researchers NTU, NUS, A*STAR and the Los Alamos National Lab have demonstrated that it is possible to inject an ultra-short pulse of spin current (less than a picosecond) from a metal to a semiconductor in a very efficient way.

The researchers used a short laser pulse on cobalt (a magnetic material) - which generated a spin-polarized "swarm" of excited electrons. The spin-polarized electrons travel outside of the material - into adjacent materials. This creates an extremely efficient spin injection.

EU's Graphene Flagship project researchers fabricated graphene-based spintronics devices that utilize both electron charge and spin at room temperature.

The researchers demonstrated the spin’s feasibility for bridging distances of up to several micrometres - which they say could open the door to single-chip devices that integrate logic and memory.