Dissipationless Multiferroic Magnonics

We propose that the magnetoelectric effect in multiferroic insulators with coplanar antiferromagnetic spiral order, such as BiFeO${}_3$, enables electrically controlled dissipationless magnonics. Applying an oscillating electric field in these materials with frequency as low as household frequency can activate Goldstone modes that manifests fast planar rotations of spins, whose motion is not obstructed by crystalline anisotropy. Combining with spin ejection mechanisms, such a fast planar rotation can deliver electricity at room temperature over a distance of the magnetic domain, which is free from the energy loss due to Gilbert damping.