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In many studies, the properties of BiFeO3–BaTiO3 (BF–BT) ceramics vary greatly using different raw reagents, which makes it challenging to obtain reliable and repeatable properties of BF–BT‐based devices. In this work, 0.7BiFeO3–0.3BaTiO3 (0.7BF–0.3BT) ceramics were fabricated by a conventional solid‐phase synthesis using TiO2 reagents with varied purities of 98%, 99%, 99.9%, and 99.99%, respectively. The phase structure, microstructure, ferroelectric, and piezoelectric properties were comprehensively studied. All compositions of the ceramics exhibit a pseudo‐cubic phase perovskite structure, and the fraction of the rhombohedral phase increases with increasing the TiO2 purity. Additionally, backscattered electron images and energy‐dispersive spectroscopy revealed an obvious core–shell structure within grains. In particular, the 0.7BF–0.3BT ceramics prepared with 98% purity TiO2 exhibited superior ferroelectric and piezoelectric properties, d33 ∼ 220 pC/N and d33∗$d_{{\mathrm{33}}}^{\;*}$ ∼ 230 pm/V. The ceramics prepared with higher purity TiO2 suffered from severe leakage conduction, which can be well addressed by adding excess TiO2. Our work reveals the importance of different grades of purity TiO2 on the electrical properties of BF–BT ceramics. [ABSTRACT FROM AUTHOR]

BiFeO3–SrTiO3 (BF–ST) ceramics have been considered a novel class of lead‐free dielectric materials exhibiting notable dielectric constants and remarkable thermal stability. In this work, we fabricated a series of (1 − x)BF–xST (0.32 ≤ x ≤ 0.44) ceramics near the morphotropic phase boundary and comprehensively investigated their microstructure and electrical properties, which seeks to optimize the piezoelectric performance. As the ST content increases, a gradual reduction in the rhombohedral phase fraction is observed alongside a corresponding increase in the cubic phase fraction. Although x = 0.38, the maximum grain size of 5.66 μm is obtained, accompanied by a distinctive heterogeneous core–shell microstructure, which demonstrates a high remanent polarization of 51.2 μC/cm2 and a maximum d33 value of 72 pC/N. Furthermore, impedance spectroscopy analysis reveals the formation of a conductive core and a nonconductive shell within the sample. These findings highlight the potential of optimized BF–ST ceramics as promising alternatives to lead‐based piezoelectric materials, offering exceptional ferroelectric and piezoelectric properties. [ABSTRACT FROM AUTHOR]

BiFeO3–BaTiO3 is a promising lead-free piezoelectric ceramic, exhibiting high Curie temperature and superior electrochemical characteristics. In this work, (1 − x) BiFeO3–xBaTiO3 (BF–xBT, x = 0. 2 6 , 0.28, 0.30, 0.32, 0.34, 0.36) ceramics were fabricated using the conventional solid-state reaction method through precise composition control. Multiple characterization techniques, including X-ray powder diffraction (XRD), scanning electron microscope (SEM), and electrical property testing systems, were applied to systematically examine the crystallographic structure, microstructure, as well as the dielectric, ferroelectric and piezoelectric properties of the BF–xBT ceramics. The XRD results confirm that all compositions exhibit a typical perovskite structure, transitioning from a single rhombohedral phase to a rhombohedral–cubic phase mixture as the BT content increases. SEM shows apparent core–shell microstructures in the ceramics. Notably, the results demonstrated that the BF–0.30BT ceramic exhibits the maximum piezoelectric constant ( d 3 3 ) ∼ 2 1 7 pC/N, while the BF–0.34BT ceramic displays the maximum converse piezoelectric constant (d 3 3 ∗) ∼ 3 2 3 pm/V, which highlights the suitability of BF–BT ceramics for high-performance piezoelectric applications. [ABSTRACT FROM AUTHOR]