April 2021

Researchers at the University of California, Riverside, have used a nanoscale synthetic antiferromagnet to control the interaction between magnons — research that could lead to faster and more energy-efficient computers.

In ferromagnets, electron spins point in the same direction. To make future computer technologies faster and more energy-efficient, spintronics research employs spin dynamics — fluctuations of the electron spins — to process information. Magnons, the quantum-mechanical units of spin fluctuations, interact with each other, leading to nonlinear features of the spin dynamics. Such nonlinearities play a central role in magnetic memory, spin torque oscillators, and many other spintronic applications.

Researchers at Aalto University have developed a new device for spintronics, which could be seen as a step towards using spintronics to make computer chips and devices for data processing and communication technology.

Schematic of the experimental geometry. Image from article

"If you use spin waves, it's transfer of spin, you don't move charge, so you don't create heating," says Professor Sebastiaan van Dijken, who leads the group that wrote the paper. The device the team made is a Fabry-Pérot resonator, a well-known tool in optics for creating beams of light with a tightly controlled wavelength. The spin-wave version made by the researchers in this work allows them to control and filter waves of spin in devices that are only a few hundreds of nanometres across.

A team of researchers from Sweden, Finland and Japan have designed a semiconductor component in which information can be efficiently exchanged between electron spin and light at room temperature and above.

Developments in spintronics in recent decades have been based on the use of metals, and these have been highly significant for the possibility of storing large amounts of data. There would, however, be several advantages in using spintronics based on semiconductors, in the same way that semiconductors form the backbone of today's electronics and photonics.

Recent studies have suggested that 2D skyrmions could be the genesis of a 3D spin pattern called hopfions, but no one had been able to experimentally prove that magnetic hopfions exist on the nanoscale. Now, a team of researchers co-led by Berkeley Lab reported the first demonstration and observation of 3D hopfions emerging from skyrmions at the nanoscale in a magnetic system.

Artist’s drawing of characteristic 3D spin texture of a magnetic hopfion. Berkeley Lab scientists have created and observed 3D hopfions. Credit: Peter Fischer and Frances Hellman/Berkeley Lab (from Phys.org)

The researchers say that their discovery is a major step forward in realizing high-density, high-speed, low-power, yet ultrastable magnetic memory devices that exploit the intrinsic power of electron spin.

A research team from the Max Planck Institute for the Structure and Dynamics of Matter (MPSD), Tianjin University in China and Tohoku University in Japan recently reported that, when driven out of equilibrium by magnetic fields, a universal Doppler effect limits the maximal spin current in magnetic insulators.

This finding is a surprising analogy to what happens in superconductors driven by electric fields and could provide a fundamental design principle for future nano-devices with computing science and power applications.

Researchers from Oak Ridge National Laboratory (ORNL), University of California and Lawrence Berkeley National Laboratory have discovered the existence of elusive spin dynamics in quantum mechanical systems.

The team successfully simulated and measured spins - magnetic particles, which can exhibit a motion known as Kardar-Parisi-Zhang in solid materials at varying temperatures. Up until now, scientists have only found evidence of the spin dynamics in soft matter and other classical materials.