Researchers demonstrate the control of spin currents at room temperature by magnon interference in haematite
In 2023, EPFL researchers succeeded in sending and storing data using charge-free magnetic waves called spin waves, rather than traditional electron flows. The team from the Lab of Nanoscale Magnetic Materials and Magnonics, led by Dirk Grundler, used radiofrequency signals to excite spin waves enough to reverse the magnetization state of tiny nanomagnets. When switched from 0 to 1, for example, this allows the nanomagnets to store digital information; a process used in computer memory, and more broadly in information and communication technologies. This work was a big step toward sustainable computing, because encoding data via spin waves (whose quasiparticles are called magnons) could eliminate the energy loss, or Joule heating, associated with electron-based devices. But at the time, the spin wave signals could not be used to reset the magnetic bits to overwrite existing data.
Now, Grundler's lab at EPFL, in collaboration with colleagues from Beihang University, ETH Zurich, Japan Atomic Energy Agency, Chinese Academy of Sciences and China's International Quantum Academy, have published a study that could make such repeated encoding possible. Specifically, they report unprecedented magnetic behavior in hematite: an iron oxide compound that is earth-abundant and much more environmentally friendly than materials currently used in spintronics.