EVIDENCE FOR DOMAIN-TYPE DYNAMICS IN THE ERGODIC PHASE OF THE PBMG1 3NB2/3O3 RELAXOR FERROELECTRIC/

It was observed that the dielectric permittivity of PbMg1/3Nb2/3O3 (PM N) relaxer ceramics increases with increasing amplitude of the applied ac field. A strong nonlinearity occurs at temperatures where the freq uency dispersion of the dielectric response is observed. A similarity was found between the effects of the amplitude and frequency on the pe rmittivity. It was shown that, taken together, these data evidence tha t the relaxation phenomena in PMN are controlled by domain-type dynami cs rather than thermally activated flips of the local spontaneous pola rization.