Temperature and frequency dependent giant magnetodielectric coupling in DyMn0.33Fe0.67O3

Perovskite DyMn0.33Fe0.67O3 experiences a paramagnetism-antiferromagnetism transition at 450K and spin reorientation at 290 K. Magnetodielectric properties were studied around the spin reorientation transition. Both giant positive and giant negative magnetodielectric coupling (MDC) were observed near room temperature. The MDC shows strong temperature and frequency dependence, and the sign changes from positive to negative when magnetic state transits from a canted antiferromagnetic state to a collinear antiferromagnetic state. Possible mechanisms are proposed based on the Maxwell-Wagner model, phase transition, the magnetoresistance effect, and spin-phonon coupling.