EVOLUTION OF THE ESR-SPECTRUM AT THE METAL-INSULATOR-TRANSITION IN QUASI-ONE-DIMENSIONAL SYSTEMS

The evolution of ESR spectra in metals containing both conduction elec trons and localized paramagnetic centers with inhomogeneous broadening of the magnetic resonance is treated theoretically. It is shown that such a spectrum can be effectively narrowed when a relaxation bottlene ck is present for an arbitrary distribution of inhomogeneous broadenin g. The temperature dependence of the ESR spectrum in the polymeric pha se of RbC60 is investigated experimentally in the region of the metal- insulator transition. Application of the calculations to the experimen tal data demonstrates good agreement with the physical model if it is assumed that the given material is a quasi-one-dimensional system. (C) 1998 American Institute of Physics. [S1063-7761(98)02103-9].