Superconductivity in the system CaLaBaCu_3-X(PO₄) _XO_7-δ with X=0.1, 0.3, 0.5

In this work, we present X-ray diffraction, Raman spectroscopy and magnetizations measurement of the system CaLaBaCu_3-X(PO ₄)_XO_7-δ with X=0.1, 0.3, 0.5 which is superconductor with the critical temperatures: T_c=20 K to X=0.1, T_c=14 K to X=0.3 and T_c=20 K to X=0.5. Samples were prepared by the solid-state reaction method under normal conditions of pressure and temperature, replacing 0.1, 0.3 and 0.5 of phosphate (PO₄) ^3- in the Cu(1) site of CaLaBaCu₃O_7-δ (La1113). The X-ray diffraction patterns revel the presence of BaCuO₂ and CuO as secondary phases, BaCuO₂ increases as phosphate increases in the samples. Rietveld refinements suggest orthorhombic crystalline structures, belonging to Pmmm spatial group, for all the samples; nevertheless there are variations in the cell parameters. T_c's were determinate by measurements of magnetization using a SQUID detection system, which indicate variation of T_c according with phosphate concentrations. An study by Raman spectroscopy is added. Finally, the chemical analysis by EDX of a scanning electronic microscope (Phillips XL30) indicates the appropriates amounts of phosphorus in the samples.