The magnetic properties of multiferroic BaCoF4

Multiferroic barium cobalt fluoride, BaCoF4, has been prepared by hydrothermal method. The antiferromagnetic structure has been confirmed, and the possible weak ferromagnetism due to Dzyaloshinskii-Moriya interaction has been excluded, from the straight line shape of applied magnetic field dependent magnetization (M-H) curve without hysteresis loop at low temperature down to 5 K. After cooling under a magnetic field, conspicuous exchange bias effect was observed at low temperature of T<50 K, which was attributed to the exchange coupling between the two phases of different spin configuration. Furthermore, significant magnetodielectric effect was observed at room temperature, which has been interpreted to the magnetic field modified weak interaction between different layers.