Shashidhar Bale

Spectroscopic investigations of Cu2+ in Li2O-Na2O-B2O3-Bi2O3 glasses

Pure and copper doped glasses with composition,xLi2O-(40-x)Na2O-50B2O3-10Bi2O3,have been prepared over the range 0 ≤x ≤ 40. The electron paramagnetic resonance (EPR) spectra of Cu2+ ions of these glasses have been recorded in the X-band at room temperature. Spin Hamiltonian parameters have been calculated. The molecular bonding coefficients, α2 and β2, have been calculated by recording the optical absorption spectra in the wavelength range 200–1200 nm. It has been observed that the site symmetry around Cu2+ ions is tetragonally distorted octahedral. The density and glass transition temperature variation with alkali content shows non-linear behaviour. The IR studies show that the glassy system contains BO3 and BO4 units in the disordered manner.

Optical absorption and electron spin resonance studies of Cu2+ in Li2O-Na2O-B2O3-As2O3 glasses

The local structure around Cu2+ ion has been examined by means of electron spin resonance and optical absorption measurements in xLi2O-(40-x)Na2O-50B2O3-10As2O3 glasses. The site symmetry around Cu2+ ions is tetragonally distorted octahedral. The ground state of Cu2+ isdx2−y2.The glass exhibited broad absorption band near infrared region and small absorption band around 548 nm, which was assigned to the2B1g →2Egtransition.

Characterization and thermal expansion of Sr2FexMo2−xO6 double perovskites

Double perovskite oxides Sr2 FexMo2−xO6 (x = 0.8, 1.0, 1.2, 1.3 and 1.4) (SFMO) of different compositions were prepared by sol–gel growth followed by annealing under reducing atmosphere conditions of H2/Ar flow. X-ray powder diffraction studies revealed that the crystal structure of the samples changes from tetragonal to cubic at around x = 1.2. Lattice parameters and unit cell volume of these samples found to decrease with the increase in Fe content. The characteristics absorption bands observed in the range 400–1000 cm−1 of Fourier transform infrared spectra indicate the presence of FeO6 and MoO6 octahedra and confirm the formation of double perovskite phase. The value of g ∼ 2.00 obtained from electron spin resonance studies indicates that Fe is in 3+ ionic state in the SFMO samples. Dilatometric studies of these samples reveal that the average value of coefficient of thermal expansion (α¯

Role of ZnO in Dc Electrical Conductivity of Lithium Bismuthate Glasses

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EPR and Optical Absorption Spectral Investigations of Cu2

) increases with the increase in temperature or Fe content in SFMO samples. The low value of coefficient of thermal expansion 1.31 × 10−6∘C−1 obtained for Sr2Fe0.8Mo1.2O6 in the present study in the temperature range of 40–100∘C makes it useful as anode material in fuel cells. The coefficient of thermal expansion (α¯

Spectroscopic and Physical Properties of Bi2O3-B2O3-ZnO-Li2O Glasses

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MIXED ALKALI EFFECT IN (40-x)K2O–xLi2O-10Na2O–50B2O3 GLASSES—PHYSICAL AND OPTICAL ABSORPTION STUDIES

) and the unit cell volume (V) of SFMO samples vary inversely with composition in agreement with Grüneisen relation.

Mixed mobile ion effect on a.c. conductivity of boroarsenate glasses

Glasses of various compositions belonging to the Bi2O3-B2O3-ZnO-Li2O quaternary system were prepared using melt quench technique. Dc electric measurements were done on the samples, and activation energies are determined. Arrhenius plots showed straight line behaviour. It is observed that the conductivity of the samples increased with temperature and also with Li2O content, whereas the activation energy decreased with Li2O content. The isothermal plots for constant ZnO and constant Bi2O3 glasses revealed that the conduction in these glasses is due to lithium ions only. The isothermal plots for constant lithium containing glasses varied nonlinearly with two maxima, which is attributed to mixed former effect. The variation is explained based on Anderson-Stuart model.

PHYSICAL AND OPTICAL POLARIZABILITY AND TRANSPORT PROPERTIES OF BISMUTHATE GLASSES

Electron paramagnetic resonance and optical absorption studies of Bi2O3-ZnO-B2O3-Li2O glasses were made by introducing Cu2

Role of Bi2O3 content on physical, optical and vibrational studies in Bi2O3-ZnO-B2O3 glasses

Bismuth glasses containing ZnO and Li2O were prepared by conventional melt-quench technique. ZnO is gradually substituted by Li2O, and its effect on various physical, thermal, and electrical conduction properties was studied and analyzed. Raman studies revealed that these glasses are mainly made up of [BiO3] and [BiO6] units. The density decreases and molar volume increases with the incorporation of Li2O into these glasses. MDSC studies have been performed on these glasses to determine the glass transition temperature and other related thermal parameters such as change in the glass transition temperature (Δ𝑇𝑔) and specific heat capacity difference (Δ𝐶𝑝). These studies revealed that the glasses possess high 𝑇𝑔 values, and 𝑇𝑔 decreases with Li2O content. The trend of these properties is attributed to the changes in the glass network structure. Dc electrical conductivity revealed that the conductivity increases and activation energy decreases with Li2O content.