Superconductivity and magnetic order in CaLaBaCu₃O_z

X-ray diffraction, thermogravimetric analysis, magnetization and Mossbauer studies of a⁵⁷Fe probe, in CaLaBa(Cu_1-xFe_x)₃O_z with z=7, 6.5 and x=0.00 to 0.05 have been performed. For z=7, T_c drops from 74 K for x=0.00 to 35 K for x=0.05. In CaLaBa(Cu_1-xFe_x)₃O_z with z=7, 10% of the iron is magnetically ordered with H_eff=530 K kOe and T_N=400 K, even though the sample is superconducting. In the oxygen poor, non-superconducting samples (z=6.5) 20% of the iron is magnetically ordered with H_eff=340 kOe and T_N=340 K. Since the iron reflects the magnetic order of the Cu(2) ions, this may show that perhaps two inequivalent Cu(2) sites exist in CaLaBa(Cu_1-xFe_x)₃O₇, ones of which is magnetically ordered. The experimental observations may be interpreted in terms of the special crystal structure which can allow superconductivity and magnetism to coexist, probably in separate Cu(2) planes.