Direct experimental determination of the crossover frequency between phonon and fracton regimes and its scaling behavior in superionic silver borate glasses

Fontana, A.; Rocca, F.; Fontana, Marco

doi:10.1103/physrevlett.58.503

Cited by 110 publications

(33 citation statements)

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“…Extended x-ray-absorption fine structure ͑EXAFS͒, 3 109 Ag NMR, 6 and x-ray diffraction 7 all support the absence of an ordered AgI phase resembling ␣-AgI. Raman spectroscopy results, on the other hand, 8 suggest the existence of such ␣-AgI domains, especially at higher AgI concentrations. While the probability of the existence of ␣-AgI microdomains is questionable, there does exist a great deal of evidence supporting the presence of disordered AgI ''microdomains.''…”

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confidence: 81%

Mid-IR and far-IR investigation of AgI-doped silver diborate glasses

Hudgens

Martin

1996

Phys. Rev. B

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The structures of xAgI+(1−x)Ag2O⋅2B2O3 glasses, where 0.2<~x<~0.6, have been investigated using midand far-infrared spectroscopy. The mid-IR spectra revealed that in those glasses prepared using AgNO3 as the starting material for Ag2O, the BO−4/BO3 ratio is constant with increasing amounts of AgI as would be expected form the proposed behavior of AgI in these glasses. However, a survey of the literature revealed those glasses prepared from pure Ag2O show a strong linear dependence of the BO−4/BO3 ratio on AgI content. Most probably, in those glasses prepared with Ag2O the Ag2O/B2O3 ratio changes with AgI content due to the decomposition of Ag2O during melting. This different behavior is associated with AgNO3 decomposing to Ag2O with heating followed by incorporation into the glassy network. For Ag2O used directly, it is proposed that it decomposes to Ag metal and O2(gas) with heating before it can be incorporated into the borate network. This latter behavior decreases with increasing AgI in the batch composition because AgI lowers the liquidus temperature of the melt considerably. The far-IR analysis of the AgI-doped silver diborate glasses suggests that there are three coordination environments for the Ag+ ions; one with iodide anions and the other two with oxygen ions. It is proposed that the separate oxygen coordination environments for the Ag+ ions arise from one with bridging oxygens of BO−4 units, and the other with nonbridging oxygens on BO−3 units. Furthermore, it is proposed that the Ag+ ions in the iodide-ion environments progressively agglomerate into disordered regions of AgI, but do not form structures similar to α-AgI. These results appear to support the conduction pathway or "microdomain" model for ionic conduction in xAgI+(1−x)Ag2O⋅2B2O3 glasses where the pathways are built up form disordered structures of AgI. Disciplines Ceramic Materials | Materials Science and Engineering CommentsThis article is from Physical Review B 53 (1996) The structures of xAgIϩ͑1Ϫx͒Ag 2 O•2B 2 O 3 glasses, where 0.2рxр0.6, have been investigated using midand far-infrared spectroscopy. The mid-IR spectra revealed that in those glasses prepared using AgNO 3 as the starting material for Ag 2 O, the BO 4 Ϫ /BO 3 ratio is constant with increasing amounts of AgI as would be expected form the proposed behavior of AgI in these glasses. However, a survey of the literature revealed those glasses prepared from pure Ag 2 O show a strong linear dependence of the BO 4 Ϫ /BO 3 ratio on AgI content. Most probably, in those glasses prepared with Ag 2 O the Ag 2 O/B 2 O 3 ratio changes with AgI content due to the decomposition of Ag 2 O during melting. This different behavior is associated with AgNO 3 decomposing to Ag 2 O with heating followed by incorporation into the glassy network. For Ag 2 O used directly, it is proposed that it decomposes to Ag metal and O 2 ͑gas͒ with heating before it can be incorporated into the borate network. This latter behavior decreases with increasing AgI in the batch composition because AgI lower...

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confidence: 81%

Mid-IR and far-IR investigation of AgI-doped silver diborate glasses

Hudgens

Martin

1996

Phys. Rev. B

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“…Hence, the possibility to uncover the true shapes of the spectral bands and to determine their spectral positions and halfwidths is strongly encumbered. Therefore, we applied a procedure that had been successfully used for other solid electrolytes [24][25][26] where the effect of Bose-Einstein statistic factor, strongly modifying the low-frequency spectral range, was taken into account. The Raman intensity with the account of Bose-Einstein factor is given by…”

Section: Raman Scattering Studiesmentioning

confidence: 99%

Phonon spectra of Cu_{6}PS_{5}Br superionic ferroelastic: experimental and theoretical studies

Studenyak¹,

Rushchanskii²,

Buchuk³

et al. 2007

Condens. Matter Phys.

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The anomalous temperature behavior of the Raman scattering bands at superionic phase transition of Cu 6 PS 5 Br is revealed. Using density functional perturbation theory within local density approximation, ab initio long-wavelength phonons have been obtained for high-symmetry cubic structure. In the calculated phonon spectrum two unstable modes indicate the experimentally observed sequence of ferroelastic and superionic phase transitions.

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“…At frequencies below some meV(~ 100cm -1 ), inelastic neutron and Raman scattering measurements show the existence of modes in excess of the predictions of Debye theory. The intensity of the maximum of the bump in the g( )/ 2 versus plot follows the Bose-Einstein law and is called the boson peak (BP) [2][3][4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%