Complex Polymorphic Behavior and Dielectric Properties of Perovskite-Related Sr(Sr1/3Nb2/3)O3

Hydrothermal derived barium niobate ultra-fine powders and nanowires

“…The Raman spectra of the powders derived from the solution of pH 14 and 15 are almost the same, which are similar to that of HT-Sr 4 Nb 2 O 9 reported by Levin and Julia [14], but they are different from those of the powders synthesized at pH 12 or 13. When pH value 14 or 15, four resonance peaks are observed at 810, 580, 420 and 320 cm −1 (the last three peaks are broad and there locations can be determined only approximately).…”

“…5 and 6, respectively. The Raman spectra of the powders derived from the solution of pH 12 or 13 show two bands in the nondegenerate symmetric region (700-1000 cm −1 ) at 790 cm −1 (strong) and 860 cm −1 (weak), corresponding to Nb-O stretching vibrations [14,15]. Another strong mode at 310 cm −1 is assigned to the symmetric stretching octahedral internal mode [16].…”

“…This is in reasonable agreement with the expected com- position of the new phase Ba 4 Nb 2 O 9 . Indexing the XRD spectra of the new compound yields an average cubic structure (Fm3m, a ≈ 2a c , where "c" refers to the cubic perovskite unit cell) with 1:1 (NaCl-type) partial ordering of Ba 2+ and Nb 5+ on the Bsites like the high-temperature polymorph of Sr 4 Nb 2 O 9 [14]. Fig.…”

Intrinsic high electrical conductivity of stoichiometricSrNbO3epitaxial thin films

“…As the growth temperature deviated from the optimal value, the resistivity drastically increased, probably owing to the off-stoichiometry mentioned previously: Excess oxygen layers introduced at lower growth temperatures compensate the electron carriers and suppress their mobility by breaking up the NbO 6 octahedral network. At higher growth temperatures, though, other defects are generated, such as Nb vacancies and Sr substitutions in the B site [20], both of which increase the Nb valence from 4+ to 5+ and thus decrease the carrier density. Figure 4 plots the resistivity and mobility of the stoichiometric SrNbO 3 epitaxial thin film as functions of temperature.…”

In pursuit of “super”high-k ternary oxides: aqueous CSD and material properties

“…The capacitances obtained for barium zirconate and strontium niobate are in the same order of magnitude as for ZrO 2 . These correspond to lower than expected k-values (~15 for barium zirconate, ~19 for strontium niobate, extracted from thickness series not shown here) compared to bulk material and thick film properties [13,14]. This can be explained by thickness effects [15], the amorphous character and possible interfacial reactions on SiO x /Si substrates [11] and thus leaves room for optimization in the deposition process.…”