Temperature dependence of polarization and strain of bismuth-based ceramic composites

Comparative study of the polarization and strain of inclusion-type and layer-type 0.94Bi(NaK)TiO3–0.06BiAlO3/Bi(NaK)TiO3 ceramic composites

“…4 shows the effective dielectric constant (ε eff ), the piezoelectric coefficient (d 33 ), and the electromechanical coupling factor (k p ) of the two composites. The ε eff of the two composites is similar to the results based on the equivalent model of the layered structure [16,24]. The ε eff of the inclusion composite follows the calculations based on the asymmetric Bruggeman model [26,27].…”

“…The XRD patterns of all the ceramics indicated a pure perovskite structure without secondary phases. According to previous studies [16,24,25], the BNKTeBA exhibited the mixed state of psuedo-cubic and tetragonal phases. Meanwhile, the BNKT showed the tetragonal phase.…”

“…A fired-on silver paste at 700 C was used as the electrode for the measurement of electrical properties. These specimens were poled in silicone oil by applying a dc field of over 5 kV/mm at 60 C. These values for the temperature and electric field for poling were chosen since the depoling temperature of BNKTeBA and BNKT were 80 C and 120 C, respectively, as reported in the previous study [24].…”

Strain Mechanisms in Lead-Free Ferroelectrics for Actuators

“…For this purpose, 0-3 BNT-based composites were designed with a macroscopically polar seed such as a ferroelectric or non-ergodic relaxor state in conjunction with a macroscopically non-polar matrix such as a paraelectric or ergodic relaxor state. [233][234][235][236][237][238][239][240] This approach allowed for an enhanced strain output with reduced hysteresis, which gave between 10 % and 30 % higher electromechanical response than solid solution materials at 4 kV/mm. 233,236 The feasibility of tailoring the temperature and frequency stability with the composite approach was also demonstrated at the expense of reduced strain output.…”

“…242,243 Apart from the effect of changing the electric field distribution, it was suggested that the electric field induced phase transformation should be aided due to heterogeneous nucleation at the interfaces between constituents. 233,234,239 Theoretically it was demonstrated that nucleation and domain switching occur through a self-organized behavior that is electrostatically controlled during initial stages and elastostatically controlled at later stages. 242 The composite approach increases the complexity of the synthesis process.…”