[Paper] Nonreciprocal microwave response at room temperature

My collaborative work at University of Tokyo with Murata manufacturing about nonreciprocal microwave response at room temperature was published in Applied Physics Letters on Nov 28, 2022. This work was selected as Editor's picks.

The breaking of both spatial-inversion and time-reversal symmetries affects the dynamics of elementary excitations; the energy and decay rate of wave vector +k become not equivalent to those of −k. This phenomenon is nonreciprocity. In our previous study, we demonstrated the magnetoelectrical control of microwave nonreciprocity in a multiferroic helimagnet at 6 K (Y. Iguchi et al. 2017). In this paper, we investigated the nonreciprocity of microwave absorption in the room temperature multiferroic helimagnet BaSrCo$_2$Fe$_{11}$AlO$_{22}$. We observed that nonreciprocal microwave absorption at 6-20 GHz at room temperature, the sign of which can be controlled by the poling electric field. Such microwave properties will open the avenue of practical applications for future wireless communications.

S. Hirose, Y. Iguchi, Y. Nii, T. Kimura, and Y. Onose
Nonreciprocal microwave response at room temperature in multiferroic Y-type hexaferrite BaSrCo$_2$Fe$_{11}$AlO$_{22}$
Appl. Phys. Lett. 121, 222401 (2022) [Editor's picks]