Domain dynamics in uniaxial relaxors

Domains in fe crystals are well-known to have a considerable influence on the value of their complex dielectric susceptibility, x = x — , X and related quantities [51], Owing to its mesoscopic character the domain wall susceptibility strongly reflects the structural properties of the crystal lattice. This is most spectacular in crystals with inherent disorder, where the 

More generally, the dynamic behavior of domain walls in random media under the influence of a periodic external field gives rise to hysteresis cycles of different shape depending on various external parameters. According to a recent theory of Nattermann et al. [54] on disordered ferroic (ferromagnetic or fe) materials, the polarization, P, is expected to display a number of different features as a function of T, frequency, / = iv/2tt, and probing ac field amplitude, E0. They are described by a series of dynamical phase transitions, whose order parameter Q = uj/2h) Pdt reflects the shape of the P vs. E loop. When increasing the ac 

Dielectric response data were taken on a Czochralski-grown very pure crystals of sisniCc (size 0.5 x 5 x 5 mm3) with probing electric-field amplitudes of 200 V/m applied along the polar c axis. A wide frequency range, 10-5 / 106 Hz, was supplied by a Solartron 1260 impedance analyzer with a 1296 dielectric interface. Different temperatures were chosen both 

Since the electric fields used in our experiments (E0 = 200 V/m) are well below the coercive field, Ec 150 kV/m, we have to account for the nonlinearity of v vs E in the 

Research Institute of Electrical Communication, Tohoku University, Japan 

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