Antiferroelectrics, ferroelectrics and pyroelectrics of a stibiotantalite structure

Low temperature firing of BiSbO4 microwave dielectric ceramic with B2O3–CuO addition

“…20 BiSbO 4 was found to crystalline with monoclinic structure [I2/c space group, a = 5.4690(2), b = 4.8847(3), c = 11.8252(6) Å, and β = 101.131(3) • ]. In our work BiSbO 4 ceramic was found to be sintered above 990 • C and exhibit dielectric constant about 19, Qf values about 70,000 GHz and TCF about −62 ppm/ • C at around 1080 • C. Its firing temperature is a little higher and this limits its application in LTCC.…”

“…6 bismuth-based microwave dielectric BiSbO 4 ceramic has been reported. 18 Single crystal of BiSbO 4 was ever synthesized by Popolitov et al 19 and the X-ray powder diffraction of BiSbO 4 was studied by Kennedy. 20 BiSbO 4 was found to crystalline with monoclinic structure [I2/c space group, a = 5.4690(2), b = 4.8847(3), c = 11.8252(6) Å, and β = 101.131(3) • ].…”

Photophysical and photocatalytic water splitting performance of stibiotantalite type-structure compounds, SbMO4 (M = Nb, Ta)

“…The estimated band gap of SbTaO 4 (3.72 eV) was larger than that of SbNbO 4 (3.12 eV). Interestingly, the band gap of SbTaO 4 was much larger, compared to a previously reported value (1.9 eV) [17], which is possibly due to the phase purity and surface defects. Since SbTaO 4 must be synthesized in vacuum or in Ar atmosphere to prevent oxidation of Sb 3þ , surface defects such as Sb 0 or oxygen defects can be generated easily [30].…”

“…NbO 6 or TaO 6 octahedra are connected by sharing four corners, and Sb 3þ ions are located in between these octahedral layers. More importantly, the Sb 3þ ions are surrounded by six oxygen atoms, forming strongly distorted SbO 6 octahedra, and this gives rise to spontaneous polarization along the c axis, thus leading to ferroelectric behavior [17,20]. The dielectric constant, a key metric for evaluating the ferroelectric properties of SbNbO 4 and SbTaO 4 is about 300e450 for the polar axis [17], which is the highest value among previously studied ferroelectric materials.…”

Synthesis, structure refinement and vibrational spectroscopy studies of the Bi1−xTa1−xTe2xO4 (0 ≤ x ≤ 0.2) solid solution with stibiotantalite type structure

“…Despite, their multiple and dielectric phase transitions, the exact nature of these transitions as well as the mechanism of ferroelectricity, still not completely understood. The syntheses, structural, and dielectric propreties of ABO 4 single crystals, have first been reviewed by Popolitov et al [2]. BiNbO 4 has the same structure as the mineral stibiotantalite (Sb 0.9 Bi 0.1 )(Ta 0.84 Nb 0.…”