2 REGIMES BEHAVIOR IN THE RESISTIVITY OF THE LA1.85SR0.15CU1-XLIXO4 SYSTEM - A SIGNATURE OF DIFFERENT ELECTRONIC STATES FOR HOLES

The variations of the normal-state resistivity and the superconducting transition temperature T-c of the La1.85Sr0.15(Cu1-xLix)O-4 system fo r 0 less than or equal to x less than or equal to 0.05 reveal a two re gimes behavior, with x congruent to 0.03 being the critical concentrat ion for a transition from a delocalized state, with a reduction of the resistivity values while T-c remains unchanged, to an early stage of a spin compensation process, characterized by T-c suppression without broadening. Disorder at the Cu-O-2 planes is proposed to be the source of localization and T-c depletion, as supported by fitting of the nor mal-state curves according to different conduction models. (C) 1997 El sevier Science Ltd.