December 2021

Researchers from Harvard University and Japan's National Institute for Materials Science have demonstrated a new way to measure the properties of spin waves in graphene.

A charge sensor measuring the cost of electrons surfing on the spin wave (green wavy lines) (Credit: Yacoby Lab/ Harvard SEAS)

Spin waves, a change in electron spin that propagates through a material, could fundamentally change how devices store and carry information. These waves, also known as magnons, don’t scatter or couple with other particles. Under the right conditions, they can even act like a superfluid, moving through a material with zero energy loss.

Researchers at Tohoku University and the University of Gothenburg have designed a new spintronics technology for brain-inspired computing.

Sophisticated cognitive tasks, such as image and speech recognition, have seen recent breakthroughs thanks to deep learning. Even so, the human brain still executes these tasks without exerting much energy and with greater efficiency than any computer. The development of energy-efficient artificial neurons capable of emulating brain-inspired processes has therefore been a major research goal for decades.

An international team has, for the first time, designed a material system that exhibits an unusually long-range Josephson effect. Regions of superconducting YBa₂Cu₃O₇ are separated by a region of half-metallic, ferromagnetic manganite (La₂/₃Sr₁/₃MnO₃) one micron wide.

When two superconducting regions are separated by a strip of non-superconducting material, a special quantum effect can occur, coupling both regions. This is known as the Josephson effect. If the spacer material is a half-metal ferromagnet, it can open up new potential applications for novel spintronic applications.