Spin-lattice relaxation of paramagnetic spin in phosphate glass under highmagnetic field

Measurements of time-resolved magnetization and AC susceptibility have been performed for copper-doped calcium metaphosphate glasses under high magnet ic field. A crossover of relaxation process was found at about 1 T. At lowe r fields below 1 T, the relaxation rate has B-0.3 dependence and changed re markably at a certain copper concentration which indicates a distance betwe en copper ions by similar to 15 Angstrom. The slow spin-lattice relaxation suggests that the vibrational excitation is localized strongly in the small area. (C) 1999 Elsevier Science B.V. All rights reserved.