NORMAL-STATE MAGNETISM OF ZN-DOPED AND OXYGEN-DEFICIENT CALABACU3O7 SUPERCONDUCTOR

Both on-site Zn substitution and oxygen deficiencies in the CaLaBaCu3O 7 system decrease the superconducting transition temperature T-c of th e pristine sample. We observed that the normal state magnetism, measur ed in a field of 5 KOe, shows a Curie-Weiss behavior, in terms of a lo calized magnetic moment, presumably on Cu sites? in both cases. The pr istine system, i.e. without Zn substitution or oxygen deficiencies, sh ows a weakly temperature dependent small magnetic susceptibility, in t he normal state, i.e. above T-c. It has been argued that the normal st ate magnetism of HTSC systems plays a vital role in determining the T- c of these materials.