The Variation of Superconducting Critical Temperature of the Mn3O4 Doped- and Mn3O4 Composited-Y145 Superconductor

Abstract

The Y145 superconductors modified with manganese oxide (Mn₃O₄) were synthesized via the solid-state reaction by using the Mn₃O₄ with various concentrations of dopant. Our research focused on the investigations of the physical and structural properties in the doping materials and the composite materials preparations. The SEM and EDX were determined the surfaces of materials and the identifications  of elements. The XRD patterns were indicated for the microstructure of these samples. The critical temperature (T_C) of the samples was measured by the four-point probe resistivity measurements. The Cu²⁺, Cu³⁺, and oxygen content were investigated by Iodometric titration. The results revealed that the influence of different concentrations of Mn₃O₄ was significantly on the increase of the T_C as increasing the Mn content in both processes. The SEM and ERD showed that the grain size of the doping samples changed slightly in comparison with the composite samples in most samples. The XRD demonstrated that the crystal structure was in the orthorhombicity. The Iodometric titration indicated that the ratio of Cu³⁺/Cu²⁺ depended on the T_C, which was rather linear dependence. The increase of T_C with increasing concentrations of Mn₃O₄ could be due to the hole filling in the CuO₂ planes.