Polymorphic phase transition and morphotropic phase boundary in Ba1−x Ca x Ti1−y Zr y O3 ceramics

Composition-dependent xBa(Zr0.2Ti0.8)O3-(1-x)(Ba0.7Ca0.3)TiO3 bulk ceramics for high energy storage applications

“…consists of a dominant second-order scattering signal which superimposes to six firstorder Raman bands, located at around 146 cm −1 (marked as peak 1), near 217 cm -1 (peak 2), a broad band around 267 cm −1 (peak 3), a weak shoulder band at 307 cm −1 (peak 4), an asymmetric band near 525 cm −1 (peak 5), and a broad weak band at 731 cm −1 (peak 6). The existence of the band at ∼150 cm −1 (1), assigned to the E (TO) mode, clearly evidences for the rhombohedral phase in all BZT-BCT compounds [35]. The peaks 2, 3, 4, 5 and 6 are assigned to A 1 (TO 1 ), A 1 (TO 2 ), B 1 , E (TO+LO), A 1 , E (TO), and A 1 , E (LO) phonon modes, respectively [30,35].…”

“…The existence of the band at ∼150 cm −1 (1), assigned to the E (TO) mode, clearly evidences for the rhombohedral phase in all BZT-BCT compounds [35]. The peaks 2, 3, 4, 5 and 6 are assigned to A 1 (TO 1 ), A 1 (TO 2 ), B 1 , E (TO+LO), A 1 , E (TO), and A 1 , E (LO) phonon modes, respectively [30,35]. The peaks at 525 cm −1 and 731 cm −1 correspond to vibrations of the Ba-O bonds, while the band at 307 cm −1 corresponds to vibrations of Ti-O bonds [35].…”

“…The peaks 2, 3, 4, 5 and 6 are assigned to A 1 (TO 1 ), A 1 (TO 2 ), B 1 , E (TO+LO), A 1 , E (TO), and A 1 , E (LO) phonon modes, respectively [30,35]. The peaks at 525 cm −1 and 731 cm −1 correspond to vibrations of the Ba-O bonds, while the band at 307 cm −1 corresponds to vibrations of Ti-O bonds [35]. The peaks near 307 cm −1 and 731 cm −1 confirm the presence of tetragonal symmetry of BZT-BCT ceramics while the peak near 150 cm -1 confirms the presence of rhombohedral structure [35].…”

“…The peaks at 525 cm −1 and 731 cm −1 correspond to vibrations of the Ba-O bonds, while the band at 307 cm −1 corresponds to vibrations of Ti-O bonds [35]. The peaks near 307 cm −1 and 731 cm −1 confirm the presence of tetragonal symmetry of BZT-BCT ceramics while the peak near 150 cm -1 confirms the presence of rhombohedral structure [35]. Therefore, the Raman spectra reveal that all the studied compositions exhibit coexistence of rhombohedral and tetragonal phases at room temperature, corresponding to MPB region.…”

Relaxor Ferroelectric Oxides: Concept to Applications

“…This term is very common in the field of complex ferroelectric solid solutions. Basically, the term 'morphotropic' referred to the crystal phase transition due to the change in the composition and which is different from the polymorphic phase boundary (PPB) [40]. PPB is generally referred to as a change in phase transition with respect to the temperature.…”