Field-induced antiferroelectric-ferroelectric phase transitions in the Pb0.98La0.02(Zr0.70Hf0.30)(1-x)TixO3 system

Field-induced phase transitions of antiferroelectric-ferroelectric nature h ave been investigated in the Pb0.98La0.02(Zr0.70Hf0.30)(1-x)TixO3 system. S amples of compositions 0.065 less than or equal to x less than or equal to 0.10, located in the vicinity of an antiferroelectric-ferroelectric phase b oundary, were analyzed by x-ray diffraction, by dielectric, and by electro- mechanical measurements. Samples with x less than or equal to 0.095 exhibit ed a metrically tetragonal structure, whereas the sample with x = 0.1 exhib ited a rhombohedral structure. From the electromechanical measurements, the compositions deepest in the antiferroelectric phase field (x less than or equal to 0.075), were initially located in the antiferroelectric phase fiel d (AFE(I)). The samples showed a pure electrostrictive behavior at low elec tric fields but underwent a phase transition into another antiferroelectric phase AFE(II) when submitted to higher electric fields. For intermediate c ompositions with 0.0775 less than or equal to x less than or equal to 0.095 , the electric field enforced a transition between the antiferroelectric AF E(II) phase and the ferroelectric phase. In the latter compositional range, remanent ferroelectric behavior was detected at zero field and increased w ith Ti content until the ferroelectric phase remained metastable, in analog y with the better studied PbNbZrSnTiO3 and PbLaZrSnTiO3 systems. (C) 2000 A merican Institute of Physics. [S0021-8979(00)08003-8].