Phase Transition and Electrical Properties of Ba_0.7Ca_0.3TiO₃–BiFeO₃ Ceramics

Abstract

Lead-free piezoelectric ceramics of (1 À x)Ba 0.70 Ca 0.30 TiO 3 -x BiFeO 3 [(1 À x)BCT-xBF, x = 0-0.065] have been prepared and investigated. The ceramics with x 0.06 have diphasic tetragonal and orthorhombic crystal structures, whereas tetragonal phase is suppressed by the introduction of BF. As a result, the composition with x = 0.065 is found to have diphasic pseudocubic and orthorhombic phases. Significantly compositiondependent grain size is observed. With increasing x from 0 to 0.065, the ferroelectric-paraelectric phase transition temperature decreases monotonically from 128°C to 50°C, accompanied by enhanced ferroelectric relaxor behavior, as indicated by the widened diffused phase transition temperature. The room temperature polarization-electric field (P-E) hysteresis loops and strain-electric field (S-E) curves indicate that the ferroelectricity enhances slightly and reaches the maximum near x = 0.05, and then weakens with increasing x. On the other hand, the piezoelectric coefficient (d 33 ) and electromechanical coupling coefficient (k p ) decrease simultaneously with increasing x, whereas the mechanical quality factor (Q m ) reaches the maximum near x = 0.05. The structure-property relationship is discussed intensively. Our results may be helpful for further understanding and designing BaTiO 3 -related lead-free ferroelectric/piezoelectric materials.

Enhanced Multiferroic and Magnetocapacitive Properties of (1 − x)Ba0.7Ca0.3TiO3–xBiFeO3 Ceramics

“…Figure (b) shows the Δ T relax of the (1− x )BCT– x BF ceramics as a function of BF content. It is found that with x increases, the Δ T relax increases and reaches the maximum of 99 for x = 0.67, and then decreases, indicating that the degree of relaxor behavior is dependent on BF content in the (1− x )BCT– x BF ceramics, consistent with our previous report …”

“…(a). For x ≤ 0.07, the decrease in T m may be ascribed to decreased internal stress in increased grain size of T phase and the local random electric fields caused by the cosubstitution of A‐site Bi 3+ and B‐site Fe 3+ , which are consistent with our previous report . For x = 0.08–0.90, the change in T m may be interpreted based on the stress model .…”

“…It is found that the compositions have diphasic T and O phases when x ≤ 0.06, characterized by the (002)/(200) splitting peaks near 2θ ~ 45°, and the O diffraction peaks. The ceramics with x = 0.065 have coexisted PC and O phases, which is consistent with previous reports . The ceramics have coexisted cubic (C) and O phases when 0.07 ≤ x ≤ 0.12.…”

Comparative Study of the Effective Properties of 0–3 and Gyroid Triply Periodic Minimal Surface Cement‐Piezocomposites

“…Different cement matrix-based piezo composites like 0-3 and 2-2 with lead zirconium titanate (PZT) piezoelectric material have already been reported in the literature. [2,4,5] Experimental results demonstrated compatibility between cement and piezoelectric inclusions and the retention of piezoelectric properties for sensor applications ensuring the potential use of such composites for sensor applications. [6] Several researchers have verified and improved the compatibility of piezoelectric inclusions within cement matrices.…”

“…But such modes of operation may not be suitable in the case of concrete‐based material due to inherent differences in material properties and volume stability. [ 2 , 3 ] This motivated the development of cement‐based piezo composites to serve structural health monitoring purposes. Different cement matrix‐based piezo composites like 0–3 and 2–2 with lead zirconium titanate (PZT) piezoelectric material have already been reported in the literature.…”