Investigation of nonstoichiometric Fe on the ferroelectric properties of BiFeO3-based piezoelectric ceramics

Enhanced comprehensive performances of piezoelectric and temperature stability are obtained in 0.725Bi(1.05)Fe(x)O(3)-0.275BaTiO(3)-0.3%MnO2 ceramics via tuning nonstoichiometric Fe content. The Fe content strongly affects the phase structure of ceramics, which possess rhombohedral-pseudocubic coexistence structure, boosting the high piezoelectricity in this system. The optimal comprehensive performances of ceramics are obtained at x = 0.98 with a relatively large piezoelectricity (d(33) similar to 158 pC/N) as well as a high Curie temperature (T-C similar to 523 degrees C). We found that the deficiency of Fe content gives rise to diffused phase boundary and oxygen vacancies, which induces strong thermal stability over a wide temperature range in the composition. This work discloses the Fe content play an important role in the crystal structure of BF-based materials. We expect that the investigation on nonstoinchiometry of Fe will lead an effective method to develop high-performance BiFeO3-based ceramics for lead-free electronic applications.