Magnetoelectric hysteresis loops in Cr2O3 at room temperature

We revisit the room-temperature linear magnetoelectric effect in Cr2O3 single crystals. It was found that the temperature dependence of dielectric constants in a magnetic field H shows a lambda-shaped peak at the Neel temperature (approximate to 307 K) and that electric polarization induced by applying H is reversed with a hysteresis by sweeping an electric field E. Similar reversal and hysteretic behaviors were also observed in the H dependence of magnetization induced by applying E. These results imply that Cr2O3 behaves as a typical ferroelectric (ferromagnet) in finite H (E) even at room temperature. We discuss the ferroic behaviors observed in the linear magnetoelectric system in the context of recent studies on multiferroics.