Field-induced antiferroelectric–ferroelectric phase transitions in the Pb0.98La0.02(Zr0.70Hf0.30)1−xTixO3 system

Abstract

Field-induced phase transitions of antiferroelectric–ferroelectric nature have been investigated in the Pb0.98La0.02(Zr0.70Hf0.30)1−xTixO3 system. Samples of compositions 0.065⩽x⩽0.10, located in the vicinity of an antiferroelectric–ferroelectric phase boundary, were analyzed by x-ray diffraction, by dielectric, and by electro-mechanical measurements. Samples with x⩽0.095 exhibited a metrically tetragonal structure, whereas the sample with x=0.1 exhibited a rhombohedral structure. From the electromechanical measurements, the compositions deepest in the antiferroelectric phase field (x⩽0.075), were initially located in the antiferroelectric phase field (AFEI). The samples showed a pure electrostrictive behavior at low electric fields but underwent a phase transition into another antiferroelectric phase AFEII when submitted to higher electric fields. For intermediate compositions with 0.0775⩽x⩽0.095, the electric field enforced a transition between the antiferroelectric AFEII phase and the ferroelectric phase. In the latter compositional range, remanent ferroelectric behavior was detected at zero field and increased with Ti content until the ferroelectric phase remained metastable, in analogy with the better studied PbNbZrSnTiO3 and PbLaZrSnTiO3 systems.