Crystal Growth and Electronic Structure of Metal Substituted BaBiO₃

Abstract

Single crystals of BaBiO3 and BaBi1-x Mo x O3 were grown by slow cooling of the molten mixture. The quality of the crystal was improved by addition of the excess BaCO3 of 20% to the mixture of starting materials with the cationic stoichiometry. Golden brown crystals grew, whose sizes ranged from 3×3×2 to 10×10×5 mm3. Quantitative analysis of BaBiO3 showed that the atomic ratios, Ba/Bi, ranged in 0.92–1.14. The oxygen stoichiometry was estimated as 2.83±0.05. The mass density was more than 96% of the calculated one. The ceramic compounds, Ba2BiInO6 and Ba2BiLaO6 were synthesized, too. It was found from the powder X-ray diffraction analysis, that the volume of Ba2BiInO6 is reduced by 5.3% of that of BaBiO3. The band structures of the compounds were examined by XPS. In Ba2BiInO6 4d level appeared below the valence band, while it was not observed in BaBi0.92Mo0.08O3.

Tuning the electronic properties at the surface of BaBiO3 thin films

“…The inset of Figure 1 intense, one at 158.1eV and 163.3eV. It is worth pointing out that photoemission experiments in bulk samples [11,12] show the presence of a single, although broad, 4f doublet, which could not be unambiguously resolved into the two components expected from the Bi charge disproportionation. In our case, it is therefore reasonable to attribute the dominant doublet to a bulk-like contribution, and the second one to the presence at the surface of Bi ions with different chemical environment.…”

Experimental and theoretical study of the electronic structure of single-crystal BaBiO3

“…The mixture was heated at the centre of the furnace to a temperature higher than the BaBiO 3 melting point of 1040 • C [62] and then was cooled down slowly with the rates given in Figure 2.2 following the reference [9]. As shown in Fig.…”

“…Trying to understand what the problem was in the last growth, we noticed in the reference paper [9] there was a temperature difference of about 3 • /cm along the length of the crucible that was not included in our growth. Introducing a temperature gradient is, in general, a well-known part in many crystal growth techniques such as in Bridgman or Zone Melting methods.…”

“…There are not as many studies on growing the parent BaBiO 3 single crystals compared to its doped superconducting compounds. However, floating zone [59] and molten flux techniques [9] have been reported to be successful in growing such single crystals. The floating zone method requires specific equipment which was not available in our laboratory at the time.…”

“…In this work a combination of solid-state+melt growth was ultimately used to grow BaBiO 3 crystals. other approach of slow-cooling the molten mixture by I. Shiozaki and H. Ishii [9] as a guidance to start. As shown below, we realized this recipe does not give us our desired big high-quality single crystals either.…”