Precursor Phenomena of Barium Titanate Single Crystals Grown Using a Solid-State Single Crystal Growth Method Studied with Inelastic Brillouin Light Scattering and Birefringence Measurements

Abstract

The nature of precursor phenomena in the paraelectric phase of ferroelectrics is one of the main questions to be resolved from a fundamental point of view. Barium titanate (BaTiO3) is one of the most representative perovskite-structured ferroelectrics intensively studied until now. The pretransitional behavior of BaTiO3 single crystal grown using a solid-state crystal growth (SSCG) method was investigated for the first time and compared to previous results. There is no melting process in the SSCG method, thus the crystal grown using a SSCG method have inherent higher levels of impurity and defect concentrations, which is a good candidate for investigating the effect of crystal quality on the precursor phenomena. The acoustic, dielectric, and piezoelectric properties, as well as birefringence, of the SSCG-grown BaTiO3 were examined over a wide temperature range. Especially, the acoustic phonon behavior was investigated in terms of Brillouin spectroscopy, which is a complementary technique to Raman spectroscopy. The obtained precursor anomalies of the SSCG-grown BaTiO3 in the cubic phase were similar to those of other single crystals, in particular, of high-quality single crystal grown by top-seeded solution growth method. These results clearly indicate that the observed precursor phenomena are common and intrinsic effect irrespective of the crystal quality.

Phase Transitions and Local Polarity above TC in a PbZr0.87Ti0.13O3 Single Crystal

“…It should be remembered that the strongest changes of elastic coefficients s 11 ' and s 11 " were also observed near T 0 (Figure 4). As in other perovskites [22][23][24], birefringence was observed far above T C = 540 K. Figure 7a shows an example of ∆n(T) run above T C and the influence of electric field on this dependence. As in the case of dielectric and elastic measurements, the temperature of 555 K has been distinguished with clear anomaly in the ∆n(T).…”

“…In the investigated crystal, the P S is the order parameter, therefore, the presence of birefringence above T C indicates once again that the phase is polar. It is worth mentioning that polar nano-regions in a macroscopically centrosymmetric lattice appear well above T C in other oxide perovskites, such as BaTiO 3 , SrTiO 3 , PbTiO 3 or PbZrO 3 :Nb (e.g., [22][23][24]26,32]).…”

“…The appearance of polar clusters in the paraelectric phase has already been observed in PZT ceramics [20,21] and even in the well-known ferroelectrics, such as BaTiO 3 (BT) crystal [22][23][24]. The existence of pertinent piezoelectric response far above T C , accompanied by strong changes in the elastic properties, was attributed to the existence of, and interaction between, polar regions in paraelectric phase.…”

“…Burns and Dacol [25] reported that the role of precursor in the paraelectric phase of BT is performed by randomly-oriented polar regions with local symmetry-breaking, while the macroscopic cubic phase is preserved. The substantial elastic anisotropy observed in the paraelectric phase of BT was attributed to temperature evolution of sizes of precursor polar clusters formed by correlated Ti motions [24,25]. Theoretical calculations reported in [26] have shown that these polar precursors, correlated with the interrelated softening of optic and acoustic modes, may appear even 80K above the phase transition temperature.…”

Novel Volatile Heteroleptic Barium Complexes Using Tetradentate Ligand and β-Diketonato Ligand

“…Heavier alkaline-earth metal compounds containing calcium, strontium, and barium are key components of magnetoresistive, ferroelectric, and piezoelectric materials for dynamic random access memory, a precursor for thin-film growth, organic synthesis, and electrically tunable microwave devices. − In particular, electroceramics containing barium oxide (BaO) and transition-metal oxides such as BaTiO 3 , BaSrTiO 3 , and Y-doped BaZrO 3 exhibit high dielectric constants and high proton conductivity. − …”