Electron-nucleus interactions in highly doped rare earth phosphate glasses

P-31 NMR measurements have been used to study the dynamics of magnetic rare earth ions in the stable metaphosphate systems (R2O3)(x)(X2O3)(0.25-x)(P2O 5)(0.75), with R = Er3+, Nd3+ and Gd3+, for varying concentrations x, where X denotes a nonmagnetic rare earth buffer. Broad EPR spectra are observabl e at liquid helium temperatures but it is not possible to measure the param agnetic relaxation time directly. Electronic relaxation parameters and crys tal field splittings have been inferred from the NMR relaxation data. Nucle i situated near paramagnetic ion sites experience shifts in resonance frequ ency due to the local field produced by the ion. The nuclear resonance line is inhomogeneously broadened with decreasing temperature and disappears ab ruptly at temperatures which depend on the magnetic ion present, its concen tration and the magnitude of the applied magnetic field. A discussion of th e line broadening process is presented.