THERMAL-STABILITY OF FIELD-FORCED AND FIELD-ASSISTED ANTIFERROELECTRIC-FERROELECTRIC PHASE-TRANSFORMATIONS IN PB(ZR,SN,TI)O3

Antiferroelectric (AFE)-ferroelectric phase transformations in tin-modified lead zirconate titanate, i.e., Pb(Zr,Sn,Ti)O3 are reported. A martensitic-type approach is developed to explain the observed thermal hysteresis and field-induced transformation behavior. A model is proposed with transformation fields where the forward E(F) and reverse E(A) field strengths are related to the transformation barrier to the ferroelectric state, and to the AFE sublattice coupling, respectively. The thermal stability of the AFE state can therefore be determined with respect to the field-induced transformation behavior. A distinction is made between field-forced and field-assisted transformations, which depend on temperature and thermal hysteresis, and which are related to reversible and irreversible field-induced characteristics. Data are reported for polarizations and strains, and discussed with respect to the proposed thermodynamic model and device applications.