Structure and properties of Er3+- modified (Bi0.5Na0.5)0.945Ba0.055TiO3-based lead-free ferroelectric ceramics

Er3+-modified (Bi0.5Na0.5)0.945Ba0.055Ti0.98(Fe0.5Sb0.5)0.02O3 (BNBT-FS) lead-free ferroelectric ceramics with large electrostrain and electrostrictive response were fabricated in our work. Results showed that Er3+-doping induced the destruction of ferroelectric order and significantly enhanced the field-induced strain. For 0.2 mol% modified sample, the unipolar strain reached 0.463 % under the electric field of 80 kV/cm, yielding a large normalized strain d33* (Smax/Emax) of 579 pm/V. For 0.4 mol% modified sample, high electrostrictive effect with temperature-insensitive electrostrictive coefficient Q33 (0.022-0.026 m4/C2 in the temperature range of 25-100 degrees C) was obtained. The large electrostrain and electrostrictive response in the present materials show the great potential of the materials for nonlinear actuators applications.