Mapping the critical current density distribution in bulk YBCO superconductors using sequential Gaussian simulation

Bulk Y123 samples with different compositions were produced by both the Top-Seeded Melt-Growth (TSMG), with a NdBCO/YBCO/MgO film (300 nm NdBCO with 20 nm YBCO buffer layer on MgO substrate) seed, and Melt-Powder-Melting-Growth (MPMG) methods. Each sample was cut into 21 small specimens after the annealing process. Magnetization measurements of the 15 specimens selected from the symmetrical regions of each cutting sample were performed. All specimens' superconducting transition temperature (Tc) values were determined to be around 92 K from the magnetization-temperature graphs. Based on the extended Bean model, the specimens' critical current densities (Jc) were calculated from the magnetization hysteresis loops. Intermediate value estimation was made with Sequential Gaussian Simulation (SGS) for the unmeasured samples using the Jcvalues of the measured samples. The Jcdistribution maps were obtained throughout each sample for different applied magnetic fields, and the results were compared.