Dielectric and Ferroelectric Properties of Thin Heteroepitaxial Films of SBN-50

Abstract

Abstract: The phase transformations and ferroelectric characteristics of thin films of barium-strontium niobate SBN-50 grown by RF-cathode sputtering in an oxygen atmosphere are studied using the dielectric spectroscopy and scanning probe microscopy (in the modes of force microscopy of the piezoresponse and Kelvin mode). It is shown that the films are characterized by a low surface roughness, an average size of ferroelectric domains ~100 nm, and spontaneous polarization directed from the substrate to the film surface. Differences in the magnitude of the surface potential signal and its relaxation for regions polarized by an external field of different polarity (+10 and –10 V) are established. The nature of the change in dielectric parameters in the temperature range T = 275–500 K indicates that the material belongs to ferroelectrics–relaxors. The reasons for the established regularities are discussed.