INFLUENCE OF THE SPIN SUSCEPTIBILITY ON THE PEAK EFFECT IN LA-DOPED CERU2

The influence of doping the Laves-phase superconductor CeRu2 with La i s studied by resistivity and magnetization measurements. As the La con centration increases the electronic mean free path and the spin suscep tibility decrease. These changes modify the pinning properties of the vortex lattice, especially the peak effect. Although the magnetic fiel d, at which the vortex lattice undergoes a crossover from weak to stro ng pinning, is increased, the pinning potential itself is not affected by the impurities. (C) 1998 Published by Elsevier Science B.V. All ri ghts reserved.