Investigation of the effects of doping in different crystal regions on the physical properties of bismuth-based (BSCCO) superconductors

In this study, BSCCO superconducting materials were prepared using the solid-state reaction method by doping different crystal regions with Na-Li co-doping, Zn doping, and K doping. The microstructural, electrical, superconducting, and hysteresis properties of the prepared doped superconducting materials were examined. All XRD patterns are similar to each other, consisting of Bi-2212 main peaks and some weak Bi-2201 and Bi-2223 peaks. The randomly oriented plate-like grains observed in the SEM images demonstrate the typical morphological characteristics of the Bi-2212 system prepared by the solid-state method. The magneto-resistance characterizations of the samples prepared with Na-Li co-doping were performed between 10 and 150 K and at magnetic field values of 0, 0.5, 1, 3, and 5 T, and were explained based on the thermally activated flux flow (TAFF) model. All samples containing Na and Li have higher activation energies (U) than the pure sample, suggesting that Na and Li dopings increase the energy barriers of the pinning centers. Similarly, all Zn and K doped samples have higher Jc values, which represents better grain morphology and a more conductive path in the intergranular regions.