Copper doped strontium Indium-borate glasses: FTIR, Raman, EPR, optical and structural studies

Abstract

Strontium borate glasses containing Indium oxide with chemical composition 69B2O3–(30-x) SrO- xIn2O3-1CuO varying ‘x’ from 0.5 to 2.5 mol% were synthesized by quenching method. The non-crystalline characteristics of these glasses were established by X-Ray diffraction patterns. Physical parameters like density (ρ), molar volume (Vm), dielectric constant (ε) and other properties were described with varying mole percent of indium oxide. Spectroscopic findings, viz. optical absorption, EPR were conducted to understand the influence of In2O3 and CuO on strontium-borate glass network. Optical energy band gap (Eopt) and Urbach energies were calculated. Spin-Hamiltonian values from EPR of Cu2+ spin probes obeyed g‖‖> g⊥>ge and A‖‖> A⊥ revealing dx2-y2 (2B1g state) as ground state of Cu2+ ions and site symmetry in the neighbourhood of Cu2+ is tetragonally distorted octahedral. FTIR studies established the existence of typical BO3, BO4 units in addition to In3+O6 groups. The various Raman peaks shown by the glass samples were appropriate assigned and corresponding structural variations were discussed.