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Abstract
At room temperature amorphous films of Pb0.76Ca0.24TiO3(PtC) were rf-sputtered onto (100)-Silicon/Ti/Pt-substrates. By a subsequent annealing at temperatures in the range from 773 K to 923 K different grain sizes between 1 and 70 nm could be prepared. The crystallization process was studied by SEM, TEM, AFM and XRD. An increase in the annealing temperatures led not only to an increasing grain size but also to cluster formation at an annealing temperature of 823 K. Brillouin spectroscopy revealed a pronounced softening of the elastic modulus and an elastic instability. The dielectric properties changed to relaxor behavior and a diffuse phase transition. Both the room temperature value and the maximum value of the dielectric constant showed a significant size dependence and consequences of the cluster formation. The relaxor behavior possibly can be explained by the formation of nanodomains similar to the polar microregions found in bulk relaxor materials like e.g. PLZT