• Syed Rahman

Articles written in Bulletin of Materials Science

• 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+ is $d_{x^2–y^2}$. The glass exhibited broad absorption band near infrared region and small absorption band around 548 nm, which was assigned to the ${}^{2}B_{1g} \rightarrow {}^{2}E_{g}$ transition.

• 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 &lt; 𝑥 &lt; 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.

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

In this article we report the study of mixed mobile ion effect (MMIE) in boroarsenate glasses. DSC and a.c. electrical conductivity studies have been carried out for 𝑥MgO–(25−𝑥)Li2O–50B2O3–25As2O3 glasses. It is observed that strength of MMIE in a.c. conductivity is less pronounced with increase in temperature and frequency. The results were explained on the basis of structural model (SM) proposed by Swenson and his co-workers supporting molecular dynamic results.

• # Bulletin of Materials Science

Current Issue
Volume 42 | Issue 3
June 2019