Anomalous elastic and dielectric behavior in nanocrystalline Ca-modified lead titanate (PTC) films

Thin amorphous PTC-films of 1 mu m thickness were produced by rf-sputtering at room temperature. A subsequent annealing process enabled us to prepare different grain sizes which have been characterised by x-ray powder diffrac tion. At the transition from the amorphous to the nanocrystalline state the elastic modulus c(11) measured by HR-Brillouin spectroscopy exhibited a su rprising instability. The dielectric constant showed not only the expected increase with increasing grain size but also a significant relaxer behavior .