Effect of granularity on the superconducting parameters of the YBa2Cu3O7−δ superconducting material

We conducted an analysis of the coherent transition behavior of the YBa2Cu3O7−δ superconducting material by varying its granular properties. Considering the sintering temperature grain size relation, we created six samples of YBa2Cu3O7−δ through solid state synthesis and subjected them to the following sintering temperatures: 860°C, 870°C, 880°C, two samples at 890°C, and one at 900°C. Once the synthesis process was completed, we characterized the samples by analyzing their crystallographic structure, morphology, and magnetic response. The Rietveld refinement of diffraction patterns confirmed the structural single phase and its crystal structure; the scanning electron microscopy images extracted an increasing relation between grain size and sintering temperature, and the magnetic analysis determined a constant critical paring temperature of Tc=93(1) K, a constant lower critical field of Hc1 = 0.5(2) kOe, and an increasing critical density current and ‘saturation’ temperature, Tsat. This behavior probably responds to Tc and Hc1 being related to the pairing transition and Tsat to the coherence transition.