Electron spin-lattice relaxation in a true amorphous material : V4+ in V 2O5

Abstract
The electron spin-lattice relaxation time T1 of V 4+ in amorphous V2O5 has been measured in the X-band between 1.4 K and 100 K : [FORMULA]. We explain this behaviour using a process requiring one two-level system (T.L.S.) modulating the crystal field, and one phonon. The characteristic temperature 56 K must be associated not with the maximum energy of the T.L.S. but with the cut-off in the distribution of the asymmetry parameter Δ. Spin-lattice relaxation is thus able to give informations about the asymmetry