Raman studies of phase transitions in gas-evaporated WO3 microcrystals

Arai, M.; Hayashi, Shinji; Yamamoto, Keiichi; Kim, S.S.

doi:10.1016/0038-1098(90)90429-f

Cited by 47 publications

(49 citation statements)

References 10 publications

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“…4(a)), while the modes of the monoclinic (I) y-phase (stable at RT) survive also as weak features or shoulders even at 40 K. Some modes having quite close frequencies to that of the N-phase were previously observed at low temperature in WO3 microcrystals [35,36], grown by an evaporation method. It is interesting to note that there is no evidence of the monoclinic (II) polar e-phase, previously reported by Salje et al in single crystals at -230 K [33,34] and in a polycrystalline sample at T < 220 K [16].…”

Section: Polymorphism Driven By Moderate Mechanicalmentioning

confidence: 78%

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Color centres and polymorphism in pure WO3 and mixed (1−x)WO3−y·xReO2 powders

Cazzanelli

Mariotto

Vinegoni

et al. 1999

Ionics

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Abstract.The relationship between structural transformations and colour centres creation is discussed for deeply coloured hydrogen tungsten bronzes and for pure WO3 powders, acquiring less intense colour after mechanical treatments of variable duration. A comparative study on coloration is made also for mixed compounds (1-x)WO3.y.xReO 2, where an evidence of a resonance effect for a particular Raman band at 970 cm -1, attributed to the color centres, is observed. Besides, it is found that even moderate milling treatments result in a quite different structural evolution of tungsten trioxide upon cooling.

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Section: Polymorphism Driven By Moderate Mechanicalmentioning

confidence: 78%

“…3(b)). To our knowledge, a Raman evidence of e-phase at RT was previously reported only for WO 3 microcrystals of size below 100 nm [35,36].…”

Section: Polymorphism Driven By Moderate Mechanicalmentioning

confidence: 90%

Color centres and polymorphism in pure WO3 and mixed (1−x)WO3−y·xReO2 powders

Cazzanelli

Mariotto

Vinegoni

et al. 1999

Ionics

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“…Thus, Raman spectroscopy was used to identify the phase composition of the product, as shown in Figure 1b. In this spectrum, peaks at 272, 324, 715 and 805 cm -1 correspond to monoclinic γ phase, the stable form of WO 3 at RT [9][10][11]. The band at 942 cm -1 can be assigned to the stretching mode of W=O terminal bonds indicating surface tungsten hydrates [10,11].…”

Section: As-sprayed Powdersmentioning

confidence: 94%

“…In this spectrum, peaks at 272, 324, 715 and 805 cm -1 correspond to monoclinic γ phase, the stable form of WO 3 at RT [9][10][11]. The band at 942 cm -1 can be assigned to the stretching mode of W=O terminal bonds indicating surface tungsten hydrates [10,11]. Peaks at 203, 272, 303, 370, 425, 642, 688 and 805 cm -1 belong to the ε phase of WO 3 .…”

Section: As-sprayed Powdersmentioning

confidence: 94%

Flame Spray Synthesis of WO3 for No Breath Monitors

Pi¹,

Wang²

2015

J Material Sci Eng

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“…These peaks were attributed to the WO 3 monoclinic phase (£) or the triclinic phase (¤). 10) The peak A was associated to OO deformation, 11) the peaks B and C were assigned to WO deformations, 12) the peaks D and E were attributed to WO stretching modes. 12) All the peaks were sharpened and shifted to the position at the higher wavenumber position between 2030°C, in particular, the peaks B and E changed remarkably.…”

Section: Raman Spectramentioning

confidence: 99%

Correlation between a dielectric anomaly and a phase transition of sintered phosphorus doped WO<sub>3</sub> ceramics

Nose

Miyazaki

Akishige

et al. 2014

J. Ceram. Soc. Japan

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Phosphorus doped WO 3 (P x W 1¹x O 3 ) ceramics were fabricated by a solid state reaction. Temperature and frequency dependence of dielectric properties for the P x W 1¹x O 3 (x = 00.15) ceramics were evaluated at the temperature between ¹20 to 80°C. The dielectric constant of the P 0.05 W 0.95 O 3 ceramic was 36005800 at the frequency range from 1 kHz to 1 MHz in the room temperature, and the dielectric loss of the P 0.05 W 0.95 O 3 ceramic were less than 0.1 at the frequency of higher than 160 kHz. The dielectric anomaly peak of the WO 3 ceramic has been observed at 20°C, and the dielectric anomaly peak of the P 0.05 W 0.95 O 3 ceramic has been observed at about 0°C. The interaction between temperature dependence of dielectric properties (dielectric anomaly) ceramics and structural change of the WO 3 and P 0.05 W 0.95 O 3 were evaluated by Raman spectra.

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Raman studies of phase transitions in gas-evaporated WO3 microcrystals

Cited by 47 publications

References 10 publications

Color centres and polymorphism in pure WO3 and mixed (1−x)WO3−y·xReO2 powders

Color centres and polymorphism in pure WO3 and mixed (1−x)WO3−y·xReO2 powders

Flame Spray Synthesis of WO3 for No Breath Monitors

Correlation between a dielectric anomaly and a phase transition of sintered phosphorus doped WO<sub>3</sub> ceramics

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