Pulse EPR spectroscopy of Cu2+-doped inorganic glasses

Two-frequency continuous-wave and pulse EPR (electron paramagnetic resonanc e) spectroscopical techniques are applied to determine static and dynamic E PR parameters of Cu2+ ions in oxide and fluoride glasses. The investigation s are focussed on the analysis of strain effects in the glassy matrices, th e identification of the magnetic nuclei in the vicinity of Cu2+ ions as wel l as the determination of the dependence of the phase memory time T-M on te mperature and resonance field. The results obtained by X-band continuous-wa ve EPR, X- and S-band echo-detected EPR, and X- and S-band electron spin ec ho envelope modulation studies of Cu2+-doped inorganic glasses yield inform ation on the local symmetry of the Cu2+ coordination polyhedra, the chemica l nature of the atoms in the second and higher coordination spheres, the di stribution of the parameters of the static spin Hamiltonian and the low-tem perature motions of the dopant-containing structural units. Special techniq ues like 2-D Mims ENDOR (electron nuclear double resonance) and hyperfine-c orrelated ENDOR are applied for the first time to doped inorganic glasses. From the spin relaxation measurements a stronger tendency of the Cu2+ ions to aggregate is found for fluoride glasses in comparison to aluminosilicate and phosphate glasses.