Skyrmions in Multiferroics

Magnetic skyrmion is a topologically stable particle-like object, which appears as nanometer-scale vortex-like spin texture in a chiral-lattice magnet. In metallic materials, electrons moving through skyrmion spin texture gain a nontrivial quantum Berry phase, which provides topological force to the underlying spin texture and enables the current-induced manipulation of magnetic skyrmion. Such electric controllability, in addition to the particle-like nature, is a promising advantage for potential spintronic device applications. In this talk, we report the experimental discovery of magnetoelectric skyrmion in an insulating chiral-lattice magnet Cu$_2$OSeO$_3$. We find that the skyrmion can magnetically induce electric polarization through the relativistic spin-orbit interaction, which implies possible manipulation of the skyrmion by external electric field without loss of joule heating. The present finding of multiferroic skyrmion may pave a new route toward the engineering of novel magnetoelectric devices with high energy efficiency.