Use of Raman spectroscopy to determine the site occupancy of dopants in BaTiO3

Abstract

Chemical doping is one of the major methods by which the properties of BaTiO3 are modified to induce various device characteristics. Doping strategies are generally separated into iso- and alio-valent (donors and acceptors) and into A- and B-site species within the perovskite structure. The A1g octahedral breathing mode at ∼800 cm−1 in BaTiO3 is Raman inactive for compositions with single B-site species. However, this mode becomes Raman active if more than one B-site species is present, including titanium vacancies, VT′′′′. Moreover, the relative intensity of the A1g breathing mode is qualitatively related to the concentration of the species replacing Ti in the B-site. This article illustrates some clear cases where the A1g octahedral breathing mode can be utilized to verify the site occupancy of dopants in BaTiO3 when used in conjunction with more conventional indirect methods such as x-ray diffraction (Vegard’s Law) and dielectric measurements as a function of temperature.

Structure–property relationships in (1−x)BaTiO3–xBiGdO3 ceramics

“…3, see Fig. 4) at about 830 cm -1 is clearly related to doping on the B site, as previously reported for Zr-doped BT (BaZrxTi1-xO3) [19]and (1-x)BaTiO3-xLaYbO3 solid solutions [5], since its intensity increases with the dopant level.…”

Effects of Bi2O3 additive on sintering process and dielectric, ferroelectric, and piezoelectric properties of (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 lead-free piezoceramics

“…Pokorný et al have stated that the appearance of A 1g mode is a good indication of doping in the B-sites of a perovskite lattice. Additionally, this peak has been hardly observed in compositions with A-site doping [41]. Therefore, it may be concluded that, beside the formation of a liquid phase during sintering, the Bi additive is also partially incorporated into the structure of BCZT + Bix samples.…”

Temperature stability, structural evolution and dielectric properties of BaTiO3–Bi(Mg2/3Ta1/3)O3 perovskite ceramics

“…The vibrational modes are indexed in the diagram. Based on the Pokorny'work[27], the modes for x = 0 were assigned as a single crystal BaTiO 3 . In the regions from low to mid-wavenumber, the Raman spectrum of pure tetragonal BaTiO 3 was characterized by a sharp band at ~170 cm -1 , a "silent" mode at ~305 cm -1 , asymmetric broader bands at ~270 cm -1 , 515 cm -1 and the high-frequency LO modes at around 715 cm -1 [28].…”