Magnetodielectric coupling and magnetization plateaus in α-CoV2O6 crystals

Large crystals of the monoclinic α-CoV2O6 cobaltite have been grown. A clear dielectric anomaly is found at 15 K which coincides with the magnetic ordering temperature. For large enough magnetic field values, this upturn in the ε′(T) curve is suppressed. This is related to the different magnetic states (antiferro (AF), ferri (FI) and ferromagnetic (FO)) revealed by the isothermal magnetization curves. At 5 K, the magnetodielectric curves are found to mimic the M(H)T = 5 K curves: two abrupt changes are observed at HC1 = 1.65 T and HC2 = 3.3 T which correspond to the AF to FI and FI to FO transitions, respectively, and also hysteretic behavior for T < 5 K. These features demonstrate the strong coupling between magnetic and dielectric order parameters.