Magnetodynamic Studies of Fine-Crystalline YBa2Cu3Oy High-Temperature Superconductor Samples Synthesized by the Sol–Gel Method

Measurements of the complex magnetic susceptibility as a function of the temperature, alternating field amplitude, and the parallel applied constant field values for a series of YBa2Cu3Oy high-temperature superconductor samples synthesized by two different methods using of the sol–gel technology have been carried out. Regularities in the change of crystalline sizes and critical superconducting parameters are determined depending on the synthesis conditions. For all the samples, both the average temperatures of the transition to the superconducting state and their ranges, which characterize the homogeneity of the sample, remain at the level of the maximum values achievable for this compound. It is concluded that different types of the nanoscale inhomogeneity of the crystalline structure manifest themselves in the differences of the temperature dependences of the transport critical current. Means of further improving the sol–gel method for producing fine-grained ceramics with desired properties are outlined.