Size-induced diffuse behavior in Pb0.89La0.11Zr0.40Ti0.60O3 nanocrystalline ferroelectric ceramics

The Pb1−xLaxZryTi1−yO3 system is a perovskite ABO3 structured material which presents ferroelectric properties and has been used as capacitors, actuators, transducers and electro-optic devices. In this paper, we describe the synthesis and the characterization of Pb0.89La0.11Zr0.40Ti0.60O3 (PLZT11) nanostructured material. The precursor polymeric method and the spark plasma sintering technique were respectively used to prepare ceramic samples. In order to compare the effect of grain size, microcrystalline PLZT11 ceramic samples were also prepared. PLZT11 samples were characterized by X-ray diffraction technique which results show a reduction on the degree of tetragonality as the average grain size decreases. Moreover, the grain size decrease to a nanometer range induces a diffuse behavior on the dielectric permittivity curves as a function of the temperature and a reduction on the dielectric permittivity magnitude. Furthermore, the large number of grain boundaries due to the nanometer size gives rise to a dielectric anomaly.

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► We prepared Pb0.89La0.11Zr0.40Ti0.60O3 nanometric ceramic by spark plasma sintering.
► Reduction on the degree of tetragonality as the average grain size decreases.
► Grain size decrease induces a diffuse phase transition on permittivity curves.
► Large number of grain boundaries gives rise to a dielectric anomaly.