Collaborative Optimization of Curie Temperature and Piezoelectricity in Ternary BiFeO₃-BiScO₃-PbTiO₃

The enhancement of piezoelectricity without compromising the Curie temperature of a piezoelectric is challenging due to phenomenological incompatibility. In the present work, the phase diagram of (0.68-x)BiFeO₃-xBiScO₃-0.32PbTiO₃, with varied addition of BiScO₃ (x = 0, 0.05, 0.10, 0.15, and 0.20), was constructed through systematic studies of the dielectric, ferroelectric, and piezoelectric properties. A rhombohedral-tetragonal phase boundary was observed near x = 0.10 BiScO₃ addition, of which the piezoelectricity was found to be seven times larger than that without BiScO₃ (∼208 pm/V vs ∼38 pm/V). Most importantly, a high Curie temperature of 430 °C is successfully inherited from binary 0.68BiFeO₃-0.32PbTiO₃. This is explained by optimized Bi compensation, which is observed critical regulating Curie temperature in BFO-based binary and ternary systems. These results open up a paradigm for collaboratively optimizing the Curie temperature and piezoelectric response for a number of ferroelectrics and provide a promising BiFeO₃-BiScO₃-PbTiO₃ film with integrated prominent performance for potential applications at elevated temperatures.