Ultra-high strain responses in lead-free (Bi0.5Na0.5)TiO3-BaTiO3-NaNbO3 ferroelectric thin films.

Lead-free (Bi 0.5 Na 0.5)TiO 3 (BNT)-based piezoelectric materials, have a great potential for high-precision actuators' applications. In this work, the high-quality (0.94- x %)(Bi 0.5 Na 0.5)TiO 3 -0.06BaTiO 3 - x %NaNbO 3 (x = 2–10, BNT-6BT- x NN) thin films have been successfully deposited on Pt/TiO 2 /SiO 2 /Si substrates by sol-gel method. An ultra-high poling strain S pol value of 1.7% with a unipolar strain S uni value of 1.47% was reported in the BNT-6BT-6NN thin films. The coexistence of the ferroelectric phase and relaxor state was observed in the compositions of x = 2–8. Furthermore, the BNT-6BT-6NN thin films show more active domain switching compared to other compositions. It is demonstrated that the optimized strain responses in the BNT-6BT-6NN are attributed to a synergistic reaction of active domain switching and reversible electric-field-induced phase transition between the ferroelectric phase and relaxor state. Our systematic study demonstrates that the BNT-6BT- x NN thin films with an improved strain response are promising candidates for the applications of miniaturized actuators. [ABSTRACT FROM AUTHOR]