International collaboration Smart lab

Assistant Professor KOHNO Ryuhei
・Spin Elastronics
Magnon, Spin, Elastronics
Research Activities

Magnons as information carriers that may replace charge currents

Is it possible to efficiently transfer information without losses? Conventional electrical devices depend on charge currents and it is inevitable to encounter the issue of energy losses due to Joule heating. One possible solution is to use electrical insulators that prohibit charge currents. We are especially interested in using fluctuations of magnetic properties propagating like waves, that is, spin waves or magnons that appear in magnetic insulators. Concretely we put emphasis on non-linear properties of magnons that resemble the diode effect. Diodes are key components in electronics. Their prized property is to provide non-linear behavior such as asymmetric conductance which allows the transport in the forward direction while blocking it in the reverse. This feature is exploited in more complex structures such as the transistor. Using magnon transport devices, we are performing a comprehensive study of the nonlinear transport properties of magnons, which are electrically emitted or absorbed inside extended YIG thin films (see figure).

Asymmetric I-V characteristics produced by magnons propagating inside an extended insulating magnetic film: the spin diode effect. The inset is a schematic of the non-local device, where magnons are electrically emitted or absorbed in the film.

Foreseeing the kick-off of Nanoterasu synchrotron radiation facilities, we are developing frameworks of new measurements with them that may contribute to better understanding and control of magnons.