Structural and dielectric properties of Er substituted sol-gel fabricated PbTiO3 thin films

Er substituted lead titanate thin films were processed via chemical solution deposition. Their structural properties were investigated by means of atomic force microscopy, X-ray diffractometry and micro-Raman spectroscopy. The Curie temperature, T-C, was obtained from dielectric measurements. The results show that the grain size, tetragonality factor, c/a, E(1TO) transverse optical phonon frequency and the ferroelectric-to-paraelectric phase transition are affected by Er doping. Particularly the lattice tetragonality and Curie temperature of Er substituted films are found to be substantially lower in comparison to undoped specimen. In contrast, the E(1TO) phonon frequency is only slightly reduced by Er doping. The Results obtained for pure and Er substituted specimens are discussed in terms of combined effects of grain size, stress development and doping on the structural characteristics.