Alkaline earth zinc borate glasses doped with Cu2+ ions studied by EPR, optical and IR techniques

• Published in: Journal of non-crystalline solids 2011-08, Vol.357 (16-17), p.3143-3152
• Main Authors: SUMALATHA, B, OMKARAM, I, RAJAVARDHANA RAO, T, LINGA RAJU, Ch
• Format: Article
• Language: English
• Subjects: Absorption spectra; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Distortion; Earth; Electron paramagnetic resonance and relaxation; Exact sciences and technology; Glass; Lattice dynamics; Magnetic properties and materials; Magnetic resonances and relaxations in condensed matter, mössbauer effect; Magnetically ordered materials: other intrinsic properties; Mathematical analysis; Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Phonon states and bands, normal modes, and phonon dispersion; Phonons and vibrations in crystal lattices; Physics; Saturation moments and magnetic susceptibilities; Spectra; Strontium; Zinc borate
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2011.05.005

Copper ions incorporated into alkaline earth zinc borate glasses 10RO+30ZnO+60B2O3 (R=Mg, Ca and Sr) and 10SrO+(30- x)ZnO+60B2O3 + xCuO (x =0, 0.1, 0.3, 0.5, and 0.7wt.%) were characterized by electron paramagnetic resonance (EPR), optical absorption and FTIR techniques. The EPR spectra of all the glass samples exhibit resonance signals characteristic of Cu2+ ions. The values of spin-Hamiltonian parameters indicate that the Cu2+ ions in alkaline earth zinc borate glasses were present in octahedral sites with tetragonal distortion. The spin concentration (N) participating in resonance was calculated as a function of temperature for strontium zinc borate (SrZB) glass sample containing 0.7wt.% of Cu2+ ions and the activation energy was calculated. From the EPR data, the paramagnetic susceptibility ( chi ) was calculated at different temperatures and the Curie constant was evaluated from the 1/ chi -T graph. The optical absorption spectra of these samples show only one absorption band. The optical band gap energies (E g) and Urbach energy ( Delta E) are calculated from their ultraviolet edges. The FTIR studies show different stretching and bending vibrations of alkaline earth zinc borate glasses.