ABSTRACT Properties of nanosize PbTiO3 are discussed from the standpoint of the effects of crystallite size on electrostrictive behavior. Experimental results based on crystallite size-dependent primary and secondary order parameters (spontaneous polarization and strain) show that the critical crystallite size (CCS) for the stabilization of the cubic paraelectric phase at 298 K is around 15 nm. The CCS inversely scales with the cubic-tetragonal transition temperature (Ttr). Electrostrictive coefficients exhibit an order of magnitude increase at 28 nm, which is attributed to the anharmonicity of the perovskite lattice. First order calculations indicate that the increase in the electrostrictive coefficients offsets the decrease in spontaneous polarization and results in an increase in piezoelectric moduli suggesting that piezoelectric activity could, in principle, be observed in the nanosize regime.
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