Structural and magnetic investigations of the xCuO(100-x) [70TeO(2) centerdot 25B(2)O(3) center dot 5SrF(2)] glasses

The xCuO(100 - x) [70Te02 . 25B(2)O(3). 5SrF(2)] vitreous system was studie d in the 0.3 less than or equal to x less than or equal to 20 mol% CuO conc entration range, by means of electron paramagnetic resonance (EPR) and magn etic susceptibility measurements. At low concentrations the Cu2+ ions are i n axially distorted octahedral symmetry units giving resonance absorptions at g approximate to 4.3. For x greater than or equal to 3 mol% CuO the copp er ions are mostly involved in clusters yielding resonance absorptions at g approximate to 2.05 in the EPR spectrum. Non-magnetic Cu+ ions are present in samples with x > 5 mol% CuO. Only dipole-dipole interactions involving the copper ions were evidenced in this glass system. Ligand field fluctuati ons were revealed in all investigated samples.