Magnetoelectrical control of nonreciprocal microwave response in a multiferroic helimagnet

摘要

Control of physical property in terms of external fields is essential forcontemporary technologies. The conductance can be controlled by a gate electricfield in a field effect transistor, which is a main component of the integratedcircuit. Optical phenomena induced by an electric field such aselectroluminescence and electrochromism are useful for display and othertechnologies. Control of microwave propagation seems also imperative for futurewireless communication technology. Microwave properties in solids are dominatedmostly by magnetic excitations, which cannot be easily controlled by anelectric field. One of the solutions for this problem is utilizing magneticallyinduced ferroelectrics (multiferroics). Here we show that microwavenonreciprocity, which is difference between oppositely propagating microwaves,can be reversed by the external electric field in a multiferroic helimagnetBa$_2$Mg$_2$Fe$_{12}$O$_{22}$. This result offers a new avenue for theelectrical control of microwave properties.