In type II multiferroics, the ferroelectricity originates from the magnetic ordering as it breaks the inversion symmetry. In this work, we investigated multiferroicity in HoFeWO₆ which belongs to the RFeWO₆ (R=Rare-earth) system recently suggested to be type II multiferroic [1]. We found that this compound orders antiferromagnetically below T_N ~17 K. Observation of an anomaly in dielectric constant and dielectric loss, as well as a polarization switchable by an electric field at the same temperature, reveal the ferroelectric nature of this transition.
We further found that below the temperature T_C2 ~5 K there appears a polarization (P₂) in opposite direction of the (P₁) at T_C1 ~17 K. While external magnetic field suppresses the polarization in the first transition (P₁), at a critical field H_C1 ~1T we observe a flipping of the direction of P₂. In addition, magnetic field dependent dielectric constant measurements show a magneto-dielectric effect of ~ 1.5% at 2 K for a critical field H_C1 ~1T. The metamagnetic behavior at low temperature with similar critical field indicates their direct relationship and the field induced nature of this observation.
[1] S. Ghara, et al, Physical Review B, 95(22) 224416 (2017)