SUPERCONDUCTIVITY, SYNTHESIS AND MAGNETISM OF CALABACU3-X(ZN,FE)(X)O-7 TETRAGONAL SYSTEM

The results of superconductivity, structure and normal state magnetism of the CaLaBaCu3-x(Zn,Fe)(x)O-7 are studies by x-ray diffraction and SQUID magnetization measurements. X-ray diffraction results show that both Zn-and Fe substitute isostructurally in CaLaBaCu3O7 system. The s uperconducting transition temperature T-c of the samples, determined f rom ac susceptibility measurements decreases with increasing Zn or Fe concentration. The relative T-c depression rate (dT(c)/dx), is larger (12K/at%) for Zn than the Fe (6K/at%) substituted samples. For both th e Zn and Fe substituted samples a Curie-Weiss behaviour is observed du e to the presumed creation of local moments on Cu for Zn doped samples , and to the magnetic moment of Fe3+/Fe4+ ions in case of Fe substitut ed samples.