Magnetoelectric effects in the skyrmion host material Cu 2 OSeO 3

Abstract

Insulating helimagnetic Cu 2 OSeO 3 shows sizeable magnetoelectric effects in its skyrmion phase. Using magnetization measurements, magneto-current analysis and dielectric spectroscopy, we provide a thorough investigation of magnetoelectric coupling, polarization and dielectric constants of the ordered magnetic and polar phases of single-crystalline Cu 2 OSeO 3 in external magnetic fields up to 150 €‰mT and at temperatures below 60 €‰K. From these measurements we construct a detailed phase diagram. Especially, the skyrmion phase and the metamagnetic transition of helical to conical spin order are characterized in detail. Finally we address the question if there is any signature of polar order that can be switched by an external electric field, which would imply multiferroic behaviour of Cu 2 OSeO 3.