EPR, FTIR, thermal and electrical properties of VO2+ doped BaCl2⋅BaO⋅B2O3 glasses

Glasses with composition xBaCl2⋅(30-x)BaO⋅68B2O3⋅2V2O5 (x = 0, 2, 5, 10, in mol%) were prepared by the conventional melt quenching technique. The Electron paramagnetic resonance (EPR) spectra have been recorded at room temperature and the Spin Hamiltonian Parameters (SHPs) of VO2+ ion were calculated. It was observed that with the increase in BaCl2:BaO ratio, the tetragonal symmetry of the V4+O6 complex was improved and there was an expansion in the 3dxy orbital. Infrared (IR) transmission spectra were recorded at room temperature using FTIR spectroscope and it was found that in glass structure, BO3 triangular units are being replaced by the BO4 tetrahedral units on addition of halide content. The glass transition temperature (Tg) and crystalline temperature (Tx) were determined using Simultaneous Thermal Analyzer (STA). The trends in Tg and Tx suggests that there is a decrease in glass stability and glass forming ability (GFA) with increasing Cl− ions content. The dc conductivity & impedance spectroscopy has been analyzed in the temperature region from 353 K to 573 K and in the frequency range from 10 Hz to 7 MHz. The frequency dependence of conductivity was found in accordance with the Jonscher’s relation.