Dielectric investigations of the (PMN)(1−x)(PT)x crystalline solution have been performed for various electrical histories. For x<0.3, relaxor behavior was observed, however the degree of diffuseness in the dielectric maximum and degree of relaxor characteristics were decreased with increasing x. Application of dc bias for x<0.33 (xc) resulted in an induced transformation to a long-range ferroelectric state. This transition had a critical threshold field (Eth). The value of Eth depended on x. For all x<xc, glasslike behavior was observed in the nonergodic temperature range for E<Eth.

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Dielectric measurements under different ac drive voltages were performed on single crystals of (PbMg1/3Nb2/3O3)(1−x)(PbTiO3)x [(PMN)(1−x)(PT)x] for 0⩽x⩽0.3. A significant increase in permittivity was observed with increasing ac drive for all compositions. The magnitude of increase depended on temperature and measurement frequency. Alternating current drive effects were found to be a low frequency phenomenon, primarily below 106 Hz. Three distinct ac-drive amplitude ranges are believed to exist in which various types of contributions dominate in the dielectric relaxation: (i) a glassy mechanism is dominant at low drives and gives rise to the typical relaxor ferroelectric characteristics in the linear dielectric response, (ii) a kink or boundary vibration type which is dominant at intermediate drives and gives rise to the nonlinearities in the dielectric response of relaxors under moderate ac drives, and (iii) a domain wall motion type which is dominant at higher drives and results in polarization reversal.