Large electric-field-induced strain and enhanced piezoelectric constant in CuO-modified BiFeO₃-BaTiO₃ ceramics

In this work, we fabricated the (1-x)BiFeO₃-xBaTiO₃+y‰ mol CuO ceramics by the modified thermal quenching technique. The pure perovskite phase was formed and a morphotropic phase boundary (MPB) was observed in the ceramics with x = 0.30-0.33. The addition of CuO can significantly enhance the density of the BiFeO₃-BaTiO₃ material. Importantly, an enhanced piezoelectric constant (d₃₃=165 pC/N), a large electric-field-induced strain (∆S = 0.54%: peak to peak strain) and a large piezoelectric actuator constant (d₃₃*=449 pm/V) together with a high Curie temperature (T_C) of 503°C were observed in the ceramics with x = 0.30 and y = 5. As a result, the enhanced piezoelectricity and large electric-field-induced strain could significantly stimulate further researches in BFO-based ceramics.