On Estimating the Critical Current Density in Polycrystalline Superconductors Synthesized by Solid-State Method

Gokhfeld, D.M.// Journal of Superconductivity and Novel Magnetism//


In a recent paper, Zhang et al. [1] studied the effect of a Pb content on the superconducting properties of Bi-2223. Some earlier, Ramírez et al. [2] explored the effect of compaction pressure on the Bi-2212. In both studies, the critical current densities were estimated and compared for a series of polycrystalline superconducting samples. The synthesis conditions for the highest critical current density were claimed in both works. This comment explains that the average granule size should be used instead of the sample size in the Bean formula for the polycrystalline superconductors synthesized by solid-state, sol–gel, electrospinning, and solution blow spinning methods. The corrected estimations for the commented articles conclude that the synthesis conditions affect both the granule size and the intragranular critical current density. The synthesis parameters for the highest critical current density conditions are clarified.