Electron paramagnetic resonance spectra of CdO-Al~2O~3-Bi~2O~3-B~2O~3 quaternary glasses containing VO~(2+) ions

摘要

Borate glasses containing different concentrations of heavy metal oxide (CdO) with 2mol% of V2O5 as the paramagnetic probe were prepared by the conventional melt quenching technique. The prepared glasses were characterized by XRD to confirm the amorphous nature. EPR and Optical absorption studies were carried out at room temperature. EPR spectra of these glass samples were recorded at X-band frequency with 100 kHz field modulation at room temperature. From the EPR spectra the spin-Hamiltonian parameters were evaluated. The spin-Hamiltonian parameter values indicated that g_(||( < g~(perpendicular) < g_e [=2.0023] and A_(//) > A~(perpendicular). This suggests that VO2+ ions are present in octahedral sites with tetragonal compression and belong to C4v symmetry with dxy being the ground state. The measure of tetragonal distortion (Δg_(//)/Δg~(perpendicular)varies non-linearly with glass composition indicating change in tetragonal distortion. The covalency rates were estimated. The number of spins participating in the resonance [N] and susceptibility (χ) values were also evaluated.