4. Conclusions and outlook

This chapter reports a systematic micro-Raman scattering study on A- and B-site doped leadbased, tungsten bronze niobate, Bi-layered, ABO3 perovskites, multiferroics and lead-free ferroelectrics. The processing conditions, substitution, temperature-dependent Raman spectra and the structure–property correlations are discussed in the ceramics and single crystal forms of these materials. It can be concluded that the Raman spectra can provide us with a lot of important physical parameters for application in the future, such as spontaneous polarization, Curie temperature, structure distortion degree, mix-phase region and phase diagram and so on. The excellent agreement between the Raman, XRD or dielectric observations of merging of phase transition temperatures in all of the ferroelectric materials with different doping compositions suggested the powerful tool for detecting phase transition with solid state spectroscopy.

It should be emphasized that the domains in these ferroelectric materials and their related phenomena with different conditions, such as electric field, magnetic field and pressure have not been well investigated. The Raman spectra can be used to characterize the species of domain (including a/c domains, 90/180 domains), critical sizes and domain wall in ferroelectrics. Thus, we can check the domain status by recording the high-resolution Raman response. Our next goal is to characterize the domain information in these ferroelectric ceramics and films and identify the factors which can affect the domain structure. We believe that our research results will be of great significance to the development of microelectronic physics in the future.
