Aging-induced double hysteresis loops in bismuth-doped (Ba,Ca)TiO_3 ferroelectric ceramics

摘要

Bismuth-doped (Ba_(1-x)Ca_x)TiO_3 ceramics (x = 0.10, Bi-BCT) were prepared by a conventional solid-state reaction technique. An abnormal double-like hysteresis polarization-electric (P-E) loop was observed at room temperature for aged Bi-BCT. Raman scattering gives critical evidence for the formation of O~(2-) vacancies in Bi-BCT. The change from the single P-E loops in the fresh samples to the double loops in the aged samples excludes the existence of a ferroelectric-antiferroelectric transition in Bi-BCT. A reversible domain switching mechanism resulting from a symmetry-conforming short-range ordering of point defects gives a reasonable explanation for the naturally age-induced double-like P-E loops in Bi-BCT.