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

Field-induced phase transitions of antiferroelectric-ferroelectric nature have been investigated in the Pb0.98La0.02(Zr0.70Hf0.30)(1-x)TixO3 system. Samples 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 boundary, were analyzed by x-ray diffraction, by dielectric, and by electro-mechanical measurements. Samples with x less than or equal to 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 less than or equal to 0.075), were initially located in the antiferroelectric phase field (AFE(I)). The samples showed a pure electrostrictive behavior at low electric fields but underwent a phase transition into another antiferroelectric phase AFE(II) when submitted to higher electric fields. For intermediate compositions 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 AFE(II) 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. (C) 2000 American Institute of Physics. [S0021-8979(00)08003-8].