Large Electric Field-Induced Strain and Antiferroelectric Behavior in (1-x)(Na_0.5Bi_0.5)TiO₃-xBaTiO₃ Ceramics

Abstract

The dielectric, ferroelectric, and electric field-induced strain response of (1-x)(Na 0.5 Bi 0.5 )TiO 3 -xBaTiO 3 (NBT-BT) (0.04 e x e 0.10) ceramics has been systematically investigated as a function of temperature. It is found that ferroelectric and antiferroelectric (AFE)-like behavior can coexist at temperatures significantly lower than the depolarization temperature T d (even down to as low as ambient temperature). Electron microscopy suggests that such behavior results from the electric field-dependence of fine scale octahedral tilt twinning disorder and the associated disorder in the local (ferroic) off-center displacements of the Na/Bi/Ba and Ti ions. The existence of the AFE-like behavior significantly enhances the electric field-induced strain. High bipolar strain of 0.40% and unipolar strain of 0.27% has thereby been achieved at ambient temperature in an NBT-BT, x = 0.07, ceramic. The bipolar and unipolar strains reach almost identical maximum values when the temperature is close to T d . Giant unipolar strains of 0.42%, 0.41%, and 0.29% were observed in NBT-BT ceramics with x = 0.06, 0.07, and 0.08 at temperatures close to their T d 's of 100°C, 50°C, and 87°C, respectively. This work thus provides new insight into ways to further optimize lead-free NBT-BT piezoelectric ceramics for practical use in different temperature ranges.

Dramatic Influence of A-Site Nonstoichiometry on the Electrical Conductivity and Conduction Mechanisms in the Perovskite Oxide Na0.5Bi0.5TiO3

“…[1][2][3][4] The perovskite oxide Na 0.5 Bi 0.5 TiO 3 (NBT) is one of the favoured candidates to replace PZT and various solid solutions with other ferroelectric materials such as BaTiO 3 and K 1-x Na x NbO 3 have been studied both for piezoelectric and high temperature capacitor (dielectric) applications. [5][6][7][8][9][10][11][12][13][14][15][16][17] NBT has a complex crystal structure. [18][19][20][21][22][23][24][25] Early neutron powder diffraction studies proposed NBT to exhibit a rhombohedral (space group R3c) structure at room temperature (RT).…”

Electric-field-induced strain contributions in morphotropic phase boundary composition of (Bi1/2Na1/2)TiO3-BaTiO3 during poling

“…35,38 Therefore, the nature of the electric-field-induced phase transformation in this material has been perceived as an establishment of long range ordering of the short range lower symmetries and simultaneous development of the corresponding lattice distortion with applied electric field. [39][40][41] In order to understand the thermodynamics of such transformations, the total free energy of any given crystallite within the polycrystalline material can be considered and written as a volume weighted sum of all the contributing factors 42…”

Enhanced piezoelectricity and nature of electric-field induced structural phase transformation in textured lead-free piezoelectric Na0.5Bi0.5TiO3-BaTiO3 ceramics

“…19,20 The high piezoelectric response and E-field induced strain in NBT based systems has been attributed to structural phase transitions under the application of E-field. [21][22][23] Similar to NBT-BT systems, NBT-KBT (Ref. 24), and NBT-BT-KNN (Ref.…”