Frequency and Temperature Response of the Polarization of Barium Titanate

Soft Mode Behavior in Cubic and Tetragonal BaTiO3Crystals and Ceramics: Review on the Results of Dielectric Spectroscopy

“…In the cubic phase, all the crystals follow a Curie-Weiss law with C = 1.67 × 10 5 K for the flux-grown crystals [12] or somewhat less from the FIR [4] and MW [1] analysis [19] (1.13 × 10 5 K), and C = 1.5 × 10 5 K [9] or 1.8 × 10 5 K [8] for the melt-grown crystals. Since the difference T C − T 0 is larger in the melt-grown crystals, maximum of the permittivity at T C is usually higher for flux-grown crystals (up to 14000) than for the melt-grown crystals (up to 9000).…”

“…It has been well established since the early sixties that there is no appreciable dielectric dispersion in the paraelectric cubic BTO crystals at least up to 60 GHz [1][2][3][4][5]. More recent papers [6,7], which claim to see a strong dispersion in the 100 MHz-1 GHz range, reported obviously an instrumental artifact, because their permittivity at 1 GHz was much too small (several hundreds) and only weakly temperature dependent, which is incompatible with the available microwave (MW) studies.…”

Size dependence of THz region dielectric properties for barium titanate fine particles

“…As a result, the high intensity reflection spectra below 100 cm −1 for the BaTiO 3 fine particles were successfully obtained for the first time. As well known, the Slater mode was an overdamped phonon mode, and the slope of the curve below 100 cm −1 increased with decreasing Slater transverse optic (TO) mode frequency [17,18]. Figure 4 shows the particle size dependence of FIR spectra below 100 cm −1 measured at 25°C.…”

“…Figure 5 shows the size dependence of the normalized slope S. Moreover, it should be noted that the reciprocal of the S value can be proportional to the Slater TO mode frequency. [17,18] However, in this study, owing to the light scattering Fig. 3 Particle size dependence of dielectric constant for the BaTiO 3 fine particles [9] reflection, it was difficult to determine the absolute value for the Slater TO mode frequency.…”

Soft-mode spectroscopy of BaTiO3 thin films

“…A strong dielectric dispersion descending down to ∼1-5 cm −1 at the Curie point (∼410 K) has been indicated by different experimental techniques 3,6,7 and assigned to the overdamped soft phonon mode. In the tetragonal phase this triply degenerate mode abruptly splits into two very distant components A 1 (TO1) and E(TO1).…”