Magnetic susceptibility study of CoO-Bi2O3-PbO glasses

The chi(-1)-f(T) of xCoO .(1 - x)[Bi2O3. PbO] glass system (0 < x less than or equal to 0.4) are investigated. The mu(eff) values for x less than or e qual to 0.01 suggest that Co2+ ions predominantly octahedrally coordinated, whereas for x greater than or equal to 0.03 the Co2+ ions are located in t etrahedral sites. For 0.01 < x less than or equal to 0.03 these two types o f coordination simultaneously exist. The paramagnetic Curie temperature ind icates negative superexchange interactions between Co2+ ions for x greater than or equal to 0.1. (C) 1999 Elsevier Science B.V. All rights reserved.