MAGNETIZATION RELAXATION IN SUPERCONDUCTING FULLERIDE K3C60 SINGLE-CRYSTALS

Magnetic relaxation processes in superconducting fulleride K3C60 are i nvestigated on monocrystalline samples in a wide range of temperatures and magnetic fields. A logarithmic time dependence M(t) of magnetizat ion is observed in samples with 100% of superconducting phase. The nor malized relaxation rate increases with temperature in the entire range of magnetic fields. The flux creep activation energy ranges from 10 t o 80 meV, and its temperature dependence has a peak. It has been concl uded from the results of measurements on samples with nonideal stoichi ometry that inhomogeneities strongly affect the relaxation processes a nd can mask the logarithmic dependence M(t) completely. (C) 1997 Ameri can Institute of Physics.