Phase transitions and phase diagram of Ba(Zr_0.2Ti_0.8)O₃-x(Ba_0.7Ca_0.3)TiO₃ Pb-free system by anelastic measurement

Strain Mechanisms in Lead-Free Ferroelectrics for Actuators

“…The triple point was called a tricritical point, although no proof on the critically was reported. 194 Recent reports indicate unambiguously the presence of two PPBs on the system 318,322,325,331,333,341 , similarly as found in other BT-based materials. 196,342 Despite the agreement of an interleaving region between R and T phases, further clearance is still required especially in the convergence region (yellow blurred shaded area), as well as the interleaving region between R and T phases.…”

“…342 Moreover, the O to T PPB is more elastic than the R to T PPB ( Figure 3.3 (c)), and displays similar elasticity as the convergence region. 318,341,349 Li et al 350 reported that the electrostrictive coefficients of BZT-BCT are ~ 0.04 m 4 /C 2 and remain relatively constant with composition and temperature. It was demonstrated that switching determines to a great extent small 323 and large 329 signal properties.…”

“…156 Recent reports also highlighted the importance of studying elastic properties of the system, as they couple with piezoelectric properties. 318,341,349 Figure 3.6 displays (a) ´ and (b) 33 as a function of composition. 322 It is observed that ´ and 33 values at the O to T PPB are higher than at the R to O PPB, similarly as reported in other BT-based materials.…”

“…345 An electric field induced phase transformation from T and R phases to an O phase has also been speculated in the literature 321 , although was not proven yet. 325 , and Xue et al 341 The shaded areas depict approximate phase stability regions. The yellow blurred shaded area indicates the phase convergence region.…”

“…340 Figure 3.4 introduces the pseudo-binary phase diagram composed of digitalized data from several literature reports. 194,325,333,341 Initially, Liu and Ren 194 proposed the presence of only one PPB from R to T phase that converge with a C phase in a triple point. The triple point was called a tricritical point, although no proof on the critically was reported.…”