Internal friction mechanism in improper ferroelectric-ferroelastic Gd2(MoO4)3

The low-frequency internal friction features of the improper ferroelectric-ferroelastic Gd2(MoO4)3(GMO) have been studied. The equilibrium state of phase transition parameters of z -orientation samples used in the experiment are not changed by the applied external mechanical stresses. The internal friction peak height is found to be proportional to the temperature rate and inversely proportional to the frequency and amplitude of mechanical stresses. A loss mechanism of mechanical energy has been proposed. According to this mechanism the internal friction peak appearing near the Curie point is due to the interaction of antiphase boundaries with domain boundaries and dislocations.