Au eklenmiş ybco üstüniletkenlerin yapısal, manyetik ve elektriksel özelliklerin incelenmesi

In this study, a systematic investigation of Au-added YBa₂Cu₃O₇₋ₓ (YBCO) samples has been undertaken mainly to understand their structural, magnetic as well as electrical behavior. In order to get high quality of superconducting bulk samples, optimum preparation conditions have been provided. The bulk samples were produced by conventional solid state reaction method at 930⁰C under the low oxygen atmosphere. The bulk samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), dc electrical resistivity (ρ-T), critical current density and ac magnetic susceptibility measurements. The samples were carried out by means of powder X-ray diffraction for phase analyses, and lattice parameters, SEM for microstructure examinations. From XRD and SEM results, an increase in the intensitiy of main peaks and average grain size but a increase in the lattice parameter c with addition of Au in comparision with the unadded sample.In addition to this, onset-offset critical transition temperature (T_c^on,T_c^off) was determined from dc electrical resistivity (ρ-T) as a function of temperature measurements. Moreover, the transition temperature (Tc) and the critical current density (Jc) are enhanced upon Au added when compared with unadded YBCO superconductor samples. The increament of Au contente decreased the transition temperature and the critical current densities values. From the AC susceptibility measurements, inter-, intra-garin peak temperature and superconducting transition temperature were determined. The possible reasons for the observed improvements in structural, magnetical and electrical properties due to the Au addition in the YBCO samples were discussed by comparison with other studies about addition of transition metals in high temperature superconductors (HTSCs).