The ternary system of x[Pb(Zn _1/3 Nb _2/3 )O ₃ . (1 - x)[Pb(ZryTi _1-y )O ₃ ] composition with “x” varying from 0.1 to 0.6 with interval of 0.1 and “y” varying from 0.46 to 0.52 with interval of 0.01 was studied. The main objective was to maximize the dielectric and electromechanical properties through compositional variation and then to establish the full property matrix of the optimized composition for further analysis and device applications. Ceramics with pure perovskite phase have been produced in the entire compositional range that was investigated. The highest ferroelectric and electromechanical properties were obtained at the 0.4[Pb(Zn _1/3 Nb _2/3 ) O ₃ -0.6[Pb(Zr _0.48 Ti _0.52 )O ₃ ]-(0.4 PZN-0.6 PZT) composition with remanent polarization (2Pr) of 74 μC/cm ² , piezoelectric charge coefficient (d ₃₃ ) of 465 pC/N, and electromechanical coupling coefficients (k _p , k _t , and k ₃₃ ) of 0.67, 0.52, and 0.77, respectively. Full property matrix for 0.4 PZN-0.6 PZT was obtained and was used as input in the finite-elements analysis of ceramics in disc and hemispherical shell form. Hollow spherical omnidirectional transducers were fabricated from the lead zinc niobate-lead zirconate titanate (PZN-PZT) ceramics as a device prototype, and underwater characteristics have been determined and reported for these transducers.

Functional properties of ferroelectric compositions depend strongly on the type of stable crystalline phase at a given temperature and texturing. In addition to defining a governing crystallographic axis among the grains with respect to a global reference axis, texturing in these systems is also often meant to imply the relationship between an external applied field and the polar axis. Here, we synthesize randomly oriented and ⟨001⟩_pc textured 0.90Pb(Mg_1/3Nb_2/3)O₃–0.10PbTiO₃ solid solutions that fall into the relaxor category. A >95% degree of ⟨001⟩_pc texturing was achieved by the use of single crystal BaTiO₃ template crystallites whose volume fraction does not exceed 5% of the entire sample volume. Electrical measurements made on random and textured samples reveal the impact of texture on the hysteresis and the dielectric response. A Curie–Weiss analysis of the temperature dependent dielectric data shows the degree of relaxor behavior in random and textured samples. As similar compositions have recently been getting interest for electrothermal management applications, we compute the electrocaloric (EC) response of the random and textured samples using indirect methods followed by an estimation of the EC response with a subsequent thermodynamic analysis to shed light on the effect of texture on the observed differences between the textured and the random oriented samples. We finally compare and contrast on the desirability of texturing in these systems for use as EC components for thermal management applications.

In this study, effects of rare-earth elements such as Nd, Gd, and Ce on the structural and the electrical properties of lead-free bismuth sodium potassium barium titanate Bi0.487Na0.427K0.06Ba0.026TiO3 (0.854BNT–0.12BKT–0.026BT) (BNKBT) ceramics have been investigated in detail. Solid-state reaction method was used to prepare undoped, 1.0 mol% Nd, 1.0 mol% Gd, 1.0 mol%, 2.1 mol%, and 2.7 mol% Ce doped BNKBT ceramic powder compositions. A pure single perovskite structure was observed in the XRD patterns for all the BNKBT ceramic systems, although doping was found to cause changes in the peak splitting and peak positions due to their site preference. The Curie temperatures have not shifted significantly with doping, but the relative permittivity values were found to have increased. The non-ergodic normal ferroelectric character of undoped BNKBT ceramic switched to an ergodic relaxor character at room temperature with Nd, Gd, and Ce doping with pinched polarization vs electric field hysteresis loops. Increased field induced strain levels were observed in the doped BNKBT ceramics with 1 mole% Ce doping yielding a giant field induced strain of 0.38% under an E-field of 65 kV/cm. Nd-doping, on the other hand, resulted in the highest releasable energy density of 0.64 J/cm3 at 65 kV/cm. Consequently, the rare-earth doped BNKBT ceramics were found to be promising for both digital actuator and high energy density capacitor applications due to their favorable electrical properties.