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.