Large strain response with low driving field in Bi 1/2 Na 1/2 TiO ₃ –Bi 1/2 K 1/2 TiO ₃ –Bi(Mg 2/3 Nb 1/3 )O ₃ ceramics

The (1− x )(0.8Bi 1/2 Na 1/2 TiO 3 –0.2Bi 1/2 K 1/2 TiO 3 )− x BiM g 2/3 Nb 1/3 O 3 (100 x BMN ) ternary solid solutions were designed and prepared using a conventional solid‐state reaction. Temperature and compositional dependent ferroelectric, piezoelectric, dielectric features, and structural evolution were systematically studied. At the critical composition of 2 BMN , a large bipolar strain of 0.43% was achieved at 55 kV/cm, and the normalized strain reaches to 862 pm/V at a low driving electric field of 40 kV/cm. It was found that the substitution of BiMg 2/3 Nb 1/3 O 3 induces a transformation from ferroelectric to relaxor phase by disrupting the long range ferroelectric order. Therefore, as the external electric field was applied, a relaxor‐ferroelectric phase transition will be induced. This is contributed to the giant strain. The results above suggest that such a ternary composition is a promising candidate for application to actuator.