Effect of Synthesis Condition on the Piezoelectric and Conductive Properties in BaTiO₃ Ceramics

Ferroelectric materials have been studied in various fields because of their unique properties, such as spontaneous polarization that can be switched by an electric field. In particular, barium titanate (BaTiO₃), which is a lead-free ferroelectric with a high dielectric constant, has been actively studied for applications in electronic devices, including energy storage applications and capacitor applications. Since electric devices have become miniaturized, the need to develop BaTiO₃ with smaller particle sizes and higher capacitance has been increasing. Although chemical modifications such as dopants, accomplished making BaTiO₃ smaller with high capacitance, there was a limitation in that macro-scale analysis techniques, which are not adequate for investigation of the nano-scale properties and mechanisms, have been mainly used. Consequently, to overcome this limitation, it is necessary to use a micro-scale characterization method to analyze the nano-sized particles. In this study, we employ piezoresponse force microscopy (PFM) and conductive atomic force microscopy (CAFM) to study BaTiO₃ ceramics according to the synthesis conditions of sintering temperatures, dopant species (Dy, Mn), and doping methods (oxide, poly). The investigation using PFM and CAFM reveals that the relative piezoresponse and leakage current depend on the sintering temperatures and dopant species. The uniformity of piezoresponse represents the dispersion of dopants which is different from doping methods. Furthermore, topography images revealed that particle size varied with the sintering temperatures, which is related to the dielectric constant. We explored the synthesis conditions that affect the piezoelectric properties and conductive properties of the BaTiO₃ ceramics using atomic force microscopy(AFM). Therefore, our findings can provide an understanding of the effect of the synthesis conditions on BaTiO₃ at a local level.