Structural and electrical properties of sodium bismuth titanate based 0–3 composite lead-free ferroelectric thick films

Future piezo-(ferro-)electric devices, in particularly the transducers with the miniaturized size require materials with thickness in micrometer scale, which limit the utilization of bulk materials due to the difficulty of thinning. Modified composite sol-gel methods turns out to be a powerful approach to fabricate thick piezo-(ferro-)electric oxide films with thicknesses of several micrometers, which satisfy the requirements of devices particularly transducers. We report the preparation of the lead-free (Bi_0·5Na_0.5)_1-xBa_xTiO₃-Bi_0.5Na_0·5TiO₃ (BNBTx%-BNT, x = 0, 0.05, 0.06, 0.07) 0–3 composite ferroelectric thick films using a modified composite sol-gel technique. The impacts of the composition of the powders and the thickness of films on the structural and electrical properties of BNBTx%-BNT composite thick films have been in-depth investigated. The dielectric, ferroelectric and piezoelectric properties of the films strongly depend on the composition of the ferroelectric powders. The most excellent electrical properties are found in BNBT6-BNT films, which have the phase at morphotropic phase boundary. These results indicate that the BNBTx%-BNT 0–3 composite thick films are a highly promising lead-free piezoelectric material for piezo-(ferro-)electric device applications like high-frequency transducers.