A neutron diffraction investigation of the structure of vitreous V2O5TeO2

Neutron and X-ray scattering studies of Li2O–TeO2–V2O5 glasses

“…Such glasses are well known to be semiconductors with relatively high conductivity and they possess memory and threshold switching functions [2][3][4]. Therefore a lot of studies have been devoted to the analysis of V 2 O 5 effects on both the structure and properties of these glasses [5][6][7][8]. Various crystalline TeO 2 polymorphs have been used as the reference material in the nuclear magnetic resonance (NMR), infrared (IR), neutron and X-ray scattering experiments [5][6][7][8].…”

“…Therefore a lot of studies have been devoted to the analysis of V 2 O 5 effects on both the structure and properties of these glasses [5][6][7][8]. Various crystalline TeO 2 polymorphs have been used as the reference material in the nuclear magnetic resonance (NMR), infrared (IR), neutron and X-ray scattering experiments [5][6][7][8]. By increasing the TeO 3 units content and decreasing the TeO 4 one, addition of V 2 O 5 has effect on short-range order of the glass.…”

Short-Range Order and Dynamics in Crystalline α-TeO2

“…Unlike crystalline α-TeO 2 , glasses have static disorder (i.e., a distribution of bond lengths) as well as thermal disorder: For the first component of the peak fit (i.e., the short bond contribution at 1.890 Å) to the correlation function for vanadium tellurite glass (shown in Figure ), the rms variation in Te–O distance is ⟨ u TeO 2 ⟩ 1/2 = 0.068 Å, and this value is typical for high real-space resolution (i.e., t-o-f neutron diffraction) studies of the structure of tellurite glasses. ,,,, This value is significantly higher than the thermal width, 0.048 Å (see Table ), of the short bond distribution in α-TeO 2 and is evidence that the glass has static disorder. If the glass has the same thermal variation in short Te–O bond length as for α-TeO 2 , then the rms variation in static short Te–O bond length in the glass is (0.068 2 – 0.048 2 ) 1/2 = 0.048 Å.…”

“…Several studies of the NLO properties of glasses have linked this behavior with the structure of the glasses and, in particular, with the presence of the lone pair (LP) of electrons on the Te 4+ ion. , The LP exerts a strong steric effect on the tellurium environment, producing an asymmetric distribution of oxygen atoms around tellurium atoms (see, for example, Figure ) and forming voids in the structure. It has been demonstrated, in a series of studies, − that the tellurium environment in a glass is altered by the addition of modifiers, such as an alkali oxide (e.g., K 2 O). This alters the NLO response, which is highest in tellurium-rich glasses comprised of [TeO 4 ] units and decreases rapidly with the addition of a modifier and the associated formation of [TeO 3 ] units. , To allow the unusual properties of tellurite glasses to be utilized effectively, an understanding of the relationship between tellurium environment, glass composition, and NLO properties is necessary.…”

Effect of composition on the spontaneous emission probabilities, stimulated emission cross-sections and local environment of Tm3+ in TeO2–WO3 glass

“…All spectra have been corrected for the spectral response of the optical apparatus. [34,35], and are therefore shifted only slightly from thulium silicates [36]. From the spectra it can be seen that the absorption into the 1 G 4 level has a double peak structure, unseen either in fluorozirconate based or silica based thulium hosts, indicating rather well defined local environments around Tm 3+ in TeO 2 +WO 3 glass.…”