Time-domain terahertz and infrared spectroscopy of BaTiO3-PVDF nanocomposites

Several composites of BaTiO3 nanoparticles obtained by mechanosynthesis embedded into a PVDF matrix were studied using time-domain THz and FTIR spectroscopies and microwave measurements with the split-post-resonator technique. No indication of the ferroelectric phase transition could be seen in the temperature dependence of the effective dielectric response, in agreement with expectations based on various effective medium models. The effective soft-mode frequency is strongly shifted up and smeared. No conclusion on the size effect of ferroelectricity can be drawn from the effective dielectric response.