Ionic Polarization Occurrence in BaSrTiO 3 Thin Film by THz-Time Domain Spectroscopy.

BaSrTiO3 thin films in a paraelectric phase were characterized on the one hand from 1 GHz to 200 GHz by microwave measurements on interdigitated capacitance and coplanar waveguides and on the other hand up to 3 THz by Time Domain Spectroscopy. An overlap of the polar nanoregion relaxation mechanism with a characteristic frequency around 800 GHz and of the ionic polarization with a relaxation frequency around 3 THz is directly evidenced experimentally. [ABSTRACT FROM PUBLISHER]