2. Experiment details

fields has great application prospect [2–5]. In recent years, complex mixed-ion ferroelectric materials have been extensively investigated in order to achieve optimum properties as well as to understand the underlying factors for property tweaking [6–9]. Therefore, the ferroelectric

The ABO3 ferroelectric materials have achieved wide usage owing to their superior electromechanical properties (Scheme 1 shows the typical structure). Investigations of bulk ferroelectric materials have demonstrated good macroscopic homogeneity of their properties and clear ferroelectric behavior [2]. However, the development of knowledge about ferroelectric behavior at the submicrometer level is relatively slow. It has been found that the structural and chemical factors such as grain size, strain, stoichiometric and compositional homogeneity and phase structure, have great effect on optimization and reproducibility of the property coefficients in ferroelectric materials [10–12]. Therefore, a further investigation should be necessary

It is important to remember that the experimentally obtained parameters depend primarily on the spatial magnitude and time-scale of the measured physical phenomena, especially for studying the structure–property correlations in these materials. Raman spectroscopy is a sensitive technique for investigating the structure modifications and lattice vibration modes, which can give the information on the changes of lattice vibrations and the occupying positions of doping ions. Structural changes that alter the crystal symmetry often have a significant effect on the Raman spectrum. In addition, spatially resolved Raman spectroscopy can be used to probe the chemical homogeneity at sub-micrometer levels. This chapter provides a review of systematic Raman scattering study on the phase transition behavior in perovskites, tungsten bronze, Aurivillius layered, multiferroics and lead-free bulk materials. The effect of A- and B-site substitutions on the Raman spectra and phase transition behavior of these materials have been studied in detail. This chapter is arranged in the following way. In Section 1, research background; In Section 2, detailed growths of the ferroelectric materials and Raman experiment; In Section 3, results of Raman spectra in PbTiO3-Bi(Mg0.5Ti0.5)O3 (PT-BMT), SrxBa1xNb2O6 (SBN), Pb11.5xLaxZr0.42Sn0.4Ti0.18O3 (PLZST), Bi1xLaxFe1yTiyO3 (BLFT) and (K0.5Na0.5)NbO3-0.05LiN

materials are considered to be one of the most practical materials in the future.

254 Raman Spectroscopy

in order to illustrate the physical mechanism in these ferroelectrics.

bO3 (KNN-LN); at last, the main results and remarks are summarized.

Scheme 1. Schematic representation of the typical ABO3 ferroelectric structure.
