DIELECTRIC PROPERTIES OF RELAXOR FERROELECTRIC (PbMg_(1/3)Nb_(2/3)O_3)_(1-x)(PbTiO_3)_x SINGLE CRYSTALS

摘要

Successive phase transitions have been observed in relaxor ferroelectric single crystals (PbMg_(1/3)Nb_(2/3)O_3)_(1-x)(PbTiO_3)_x (PMN-xPT) for x=0.24. 0.31 and 0.33, by using dielectric measurements and polarization-electric field (P-E) hysteresis loops. Phase coexistence that is characterized by broad dielectric maxiumum and gradual-evolution of remanent polarization, has been observed in these crystals. The field-cooled-zero-field-heated dielectric permittivity shows that the dc bias field induces a long-range ferroelectric phase transition.