Marjaneh Jafari Fesharaki,
Volume 21, Issue 0 (3-2024)
Abstract
The structural, dielectric, and ferroelectric properties of (1−x)PFN–PT/x(Ca,Sr)ZrO₃ ceramics (x = 0–0.08) were systematically investigated. X-ray diffraction analysis confirmed the formation of a single-phase perovskite structure, while Rietveld refinement revealed a gradual reduction in the monoclinic lattice distortion with increasing CZ and SZ contents, indicating structural evolution toward a pseudocubic-like state near the morphotropic phase boundary (MPB). Quantitative FE-SEM analysis showed dense microstructures with progressive grain refinement at higher modifier concentrations. Temperature-dependent dielectric measurements exhibited the highest dielectric constant for the x = 0.04 compositions, whereas the modified Curie–Weiss analysis confirmed diffuse phase transition and relaxor behavior, with γ values of 1.94 and 1.68 for PFN–PT:0.04CZ and PFN–PT:0.04SZ, respectively. Room-temperature ferroelectric measurements yielded maximum remanent polarization (Pr) values of 24.32 and 34.26 μC cm⁻² for the CZ- and SZ-modified ceramics at x = 0.04. The enhanced dielectric and ferroelectric properties are closely correlated with the reduced monoclinic distortion near the MPB, highlighting the crucial role of structural optimization in improving the functional performance of PFN–PT-based ceramics.
Ram Chhavi Sharma,
Volume 22, Issue 1 (3-2025)
Abstract
The effect of different Nd and PT compositions on the electrical and ferroelectric properties of (1-y)Bi1-xNdxFeO3-yPbTiO3 solid solutions, where x = 0.05, 0.10, 0.15, 0.20 and y = 0.1, 0.2, 0.3, and 0.4, was investigated to optimise material performance. Nd doping enhances the frequency-dependent dielectric properties of produced solid solutions. However, an anomaly in the dielectric loss tangent, which is consistent with the Debye relaxation process, is observed for compositions with x˂0.10 and y≥0.2 values in the frequency range of 1 KHz to 1 MHz. Dielectric anomalies were more noticeable around the transition temperature in temperature-dependent dielectric characteristics plots, suggesting stronger magnetoelectric interactions. The decrease in the dielectric constant for solid solution compositions with y ≥0.3 indicates the presence of MPB with BFO due to an increase in the tetragonal phase of the PbTiO3 compound. As Nd content increases, temperature-dependent dielectric permittivity predicts relaxor-type ferroelectric performance for y=0.4 composition of solid solutions. A ferroelectric investigation showed that saturation polarisation, remnant polarisation, and coercive field of all prepared solid solutions decrease with increased Nd doping. However, for y˃0.3 composition, a substantial rise in these parameters was observed, which is a result of electric order dominating over magnetic order in solid solutions. The study reveals that Nd doping reduces leakage current, making it a promising contender for future applications
