Dielectric and ferroelectric properties of BTFCO thin films

Abstract

Single phase Bi3.25La0.75Ti2.5Nb0.25Fe0.125Co0.125O12 (BTFCO) thin films were deposited on Pt/TiO2/SiO2/Si substrates by RF-magnetron sputtering. Ferroelectric domain switching, including 180° and non-180° domains walls, was observed in polarization- electrical field hysteresis loops. The coercive field Ec of the materials, linking with zero polarization, is near 100 kV/cm. Dielectric permittivity changing with DC electric field shows one permittivity peak near 50 kV/cm, which suggests that field induced switching of 180° domains is completed at 50 kV/cm. Further increasing the DC field causes the decrease of dielectric permittivity, which can be attributed to the decrease of density of 90° domain walls. The difference between the Ec and the field for permittivity peak show that the switching field of 180° domain is lower than that of 90° domains in BTFCO ferroelectric films.