The origin of the ferroelectricity in the bismuth titanate Bi_4Ti_3O_(12) with perovskite-like layered structure

摘要

The goal of this study was to investigate the origin of ferroelectricity in Bi_4Ti_3O_(12). The bismuth titanate Bi_4Ti_3O_(12) (BTO), which belongs to the Aurivillius family, is one of the most interesting compounds among the bismuth-based layered ceramics. BTO is a ferroelectric material with wide applications in the electronic industry, as capacitors, transducers, memory devices and sensors. Aurivillius structures are described with a general formula following form: A_(m-1)Bi_2B_mO_(3m+3). BTO ceramic material is an Aurivillius structure with m = 3. This ceramic material was prepared by the conventional mixed-oxide method of the solid state reaction. The temperature of the Bi_4Ti_3O_(12) sintering was selected on the basis of thermogravimetric studies. The crystal structure of Bi_4Ti_3O_(i2) was examined at room temperature with X-ray diffraction analysis. The phase formation behavior was investigated using thermogravimetric (TG) and differential thermal analysis (DTA). The microstructure was investigated by Scanning Electron Microscopy (SEM) studies. Based on the Dorrian's model, the value of displacements between bismuth ions and oxygen octahedra was calculated.