Electron Paramagnetic Resonance and Optical Absorption Studies on Copper Ions in Mixed Alkali Cadmium Phosphate Glasses

Electron paramagnetic resonance (EPR) and optical absorption studies were carried out at room temperature on copper doped mixed alkali cadmium phosphate (LiNaCdP) glasses to understand the nature and symmetry of dopant. Three samples with varying concentrations of alkali ions have been prepared. The spin Hamiltonian parameters obtained from room temperature EPR spectra are: g(parallel to)=2.437, g(perpendicular to)=2.096, A(parallel to)=117x10(-4) cm(-1), A(perpendicular to)=26x 10(-4) cm(-1) for LiNaCdP1, g(parallel to)=2.441, g(perpendicular to)=2.088, A(parallel to)=121x10(-4) cm(-1), A(perpendicular to)=25x10(-4) cm(-1) for LiNaCdP2 and g(parallel to)=2.433, g(perpendicular to)=2.096, A(parallel to)=125x10(-4) cm(-1), A(perpendicular to)=32x10(-4) cm(-1) for LiNaCdP3. These EPR results indicate that the dopant Cu2+ ion enters the glass matrix into a tetragonally elongated octahedral site. The bonding parameters evaluated by correlating optical and EPR data suggest that bonding between the central metal ion and ligands is partially covalent. The mixed alkali effect in cadmium phosphate glasses was reported.