Generalized susceptibility of dislocations in ferroelectrics and ferromagnetics

Abstract

Abstract A generalized susceptibility of dislocations is calculated in ferroelectrics and ferromagnetics and also in the vicinity of a structural phase transition point by which natural frequencies for dislocations are defined, when the fariation of the order parameter η is not related with long-range fields. Two existing vibration branches are shown: “quasiacoustic”, whose frequency tend to zero at q → 0, where q is the wave vector of the bending wave, propagating along the dislocation, and “quasioptical”, splitting out from the edge of the optical zone of the crystal vibrations. A noticeable contribution to the damping of the dislocation vibrations is shown to be related with energy dissipation at vibrations of the order parameter η.