Herein we report the study of the influence of synthesis conditions during the microwave-hydrothermal crystallization of freshly precipitated gels on the phase composition and morphology of the ...rare-earth doped yttrium orthophosphates nanoparticles. We characterize the nanoparticles of YPO sub(4) and YPO sub(4) times 0.8H sub(2)O using X-ray diffraction analysis, TEM, and FT-IR spectroscopy. Furthermore, we argue that for the given phase the degree of crystallinity and thus the sample morphology depend strongly on the synthesis conditions. We establish that the hexagonal hydrate phase can be obtained by means of microwave-hydrothermal method if one uses phosphate anion excess or adjusts pH of the reaction mixture. Also we show that the metastable hydrate phase is most likely stabilized by hydroxyl groups at elevated temperatures.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We have developed a process for the synthesis of fine bismuth orthogermanate, Bi
4
Ge
3
O
12
(BGO), powders in a NaCl/KCl melt and examined the effect of synthesis conditions on the phase composition ...and morphology of the powders. Our results demonstrate that the synthesized materials compare well in scintillation performance with single-crystal BGO: their scintillation efficiency is 90% relative to single-crystal BGO, with a decay time of 300 ns.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
A technique has been developed for fluorinating the pyrochlore oxide Bi
1.8
Fe
0.2
FeSbO
7
, and a compound with the composition Bi
1.8
Fe
1.2
SbO
7–x/2
F
x
has been obtained. The synthesized ...oxyfluoride also has the pyrochlore structure (sp. gr.
Fd
3
m
), with a lattice parameter a = 10.4443(1) Å (
R
wp
= 5.2). It has been shown that the charge balance upon fluorine substitution for oxygen is maintained not through partial reduction of Fe
3+
to Fe
2+
but through the incorporation of fluorine into oxygen vacancies. The magnetic behavior of the fluorinated pyrochlore phase is determined by the persisting frustration of the octahedral sublattice, which is responsible for the development of a spin glass state below
T
f
= 12 K. The fluorination-induced changes in the anion sublattice led to an increase in the antiferromagnetic exchange interaction between neighboring Fe
3+
ions and changes in the dynamic properties of the spin glass phase.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Experimental data have been presented to confirm the thermal nature of broadband visible radiation emitted from Yb
3+
- and Er
3+
-doped nanocrystalline particles of orthophosphates and ...orthophosphate hydrates irradiated by 972-nm near-infrared laser radiation. The mechanism of appearance of this radiation has been discussed.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Reactions of nitric acid solutions of bismuth with alkalis have been studied. The effect caused by coprecipitation conditions in the presence of additional agents (EG, PEG 400, or PEG 8000) and ...without on the phase composition and morphology of α- and γ-Bi
2
O
3
has been determined.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
—We have synthesized needle- and platelike α-Bi
2
O
3
and Bi
2
O
2
CO
3
nanoparticles. The bulk density of the α-Bi
2
O
3
and Bi
2
O
2
CO
3
powders is 8.5 and 6.9 g/cm
3
. The dielectric permittivity ...of α-Bi
2
O
3
and Bi
2
O
2
CO
3
has been calculated using dielectric permittivity and dielectric loss tangent dispersion measurements in the frequency range from 2.5 × 10
1
to 1 × 10
6
Hz for 40% suspensions (0.05 and 0.08 volume fractions of α-Bi
2
O
3
and Bi
2
O
2
CO
3
, respectively) in PMS-300 polydimethylsiloxane. The value of ε
∞
has been found to be 5.4 for α-Bi
2
O
3
and 4.9 for Bi
2
O
2
CO
3
. Dielectric spectra of the suspensions have been shown to exhibit no relaxation behavior in the frequency range studied. We have compared the effects of the shape and dielectric permittivity of the particles on the magnitude of the electrorheological effect in them. Using a simple polarization model, we have analyzed the effect of the dielectric characteristics of the filler material on the yield stress τ
0
of the suspensions in electric fields from 0 to 4 kV/mm. Using a combination of rheometric and direct microscopic observations, we have explained the effect of the type of filler on the electrorheological effect: the Bi
2
O
2
CO
3
-based ERFs have higher shear and compressive yield stresses, whereas the α-Bi
2
O
3
-based ERFs have a higher tensile yield stress.
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Anhydrous basic bismuth nitrate Bi
6
(NO
3
)
2
O
7
(OH)
2
was shown to be produced by reacting bismuth nitrate with aqueous ammonia under microwave-assisted hydrothermal treatment as a result of ...hydrolysis. The composition of the basic nitrate was verified by titration, CHNS analyses, DTG, and IR spectroscopy. Photocatalytic tests showed that Bi
6
(NO
3
)
2
O
7
(OH)
2
has a photocatalytic activity, but its properties are interior to those of α-Bi
2
O
3
.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
8.
Synthesis of nanocrystalline BiSbO4 Egorysheva, A. V.; Berseneva, A. A.; Kuvshinova, T. B. ...
Russian journal of inorganic chemistry,
09/2017, Volume:
62, Issue:
9
Journal Article
Peer reviewed
Reaction of hydrochloric acid solutions of bismuth and antimony with ammonia has been studied and effect of coprecipitation conditions of resultant hydroxides on their reactivity has been determined. ...Annealing conditions for coprecipitation products have been optimized. Effect of surfactants of different nature and concentration on the phase composition, size, and shape of resulting particles have been examined. Nanocrystalline samples of BiSbO
4
have been synthesized.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Optical and vibrational spectra of Bi1.8Fe1.2(1 – x)Ga1.2xSbO7 solid solutions with pyrochlore structure have been studied. It has been shown that the compounds have strongly disordered structure. It ...has been established that a decrease in iron content causes a marked shift of Bi1.8Fe1.2(1 – x)Ga1.2xSbO7 absorption edge. According to assessment of band gap width, Bi1.8Ga1.2SbO7 is the most wide-band compound (2.90 eV), while Bi1.8Fe1.2SbO7 is the most narrow-band compound (1.88 eV).
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The Bi–La–Fe–Sb–O, Pr–Fe–Sb–O, and Bi–Pr–Fe–Sb–O systems have been shown to contain pyrochlore solid solutions. We have determined the limits of the Pr2–xFe1 + xSbO7 and Bi2–xLnxFeSbO7 (Ln = La, Pr) ...solid solutions and shown that there is no compound corresponding to the “ideal” composition Pr2FeSbO7. Analysis of the magnetic properties of the synthesized compounds indicates that rare earth substitution for bismuth ions has no effect on the spin glass transition and that the spin glass state is only determined by the interaction between the Fe3+ spins on the octahedral site. The Pr3+ paramagnetic ion in Pr2–xFe1 + xSbO7 does not participate in the formation of the spin glass state but makes a paramagnetic contribution to the total magnetic susceptibility, which is especially significant at low temperatures.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
