Raman spectroscopy on nano-structured relaxor ferroelectrics

Written by V. K.Veerapandiyan & M. Deluca - Materials Center Leoben Forschung GmbH - Leoben, Austria

What is the fundamental physics behind the relaxor behaviour in barium-based perovskites? This is the motivation behind our latest project at Materials Center Leoben Forschung GmbH (MCL), led by Dr. Marco Deluca and funded by the Austrian Science Foundation (FWF-Project P29563-N36). Raman spectroscopy (RS) will be utilized to perform structural characterization on selected lead-free Ba-based solid solutions as a function of temperature (T) and applied electric field (E). Macroscopic material properties including dielectric measurements and P-E hysteresis measurements will be performed to complement the spectroscopic results. A theoretical approach will be made to calculate the Raman spectra using ab initio and molecular dynamics simulations and will be compared against the experimental observations. 

It is expected that the project will play a vital role in improving the fundamental understanding about relaxor-ferroelectrics (RF) especially lead free RF following many genuine efforts to replace lead in piezo-electric ceramics by the global scientific community. E-field dependent Raman studies are still not abundantly available in the literature and are considered very important for these materials since RF are mostly chemically substituted material systems and these substitutions at atomic level influence the way local polarisation responds to E-fields with different frequency. The main outcome of the project is to extend the usefulness of RS to study highly disordered ceramics and to help the scientific community speed up the search for a better performing lead-free RF ceramic.

Unraveling the science behind relaxation behaviour in lead-free relaxor ferroelectric ceramics.