Macroscopic persistent currents in high temperature ceramic superconductors

We study the macroscopic persistent currents (PC) in a thick cylindrical shell of ceramic high temperature superconductors (HTS) in the framework of a generalized Ginzburg-Landau theory (GGL), based on the coexistence of antiferromagnetism and superconductivity. It is shown that, in the absence of the applied magnetic field, the PC differ in nature from the current associated with the Meissner effect. Moreover, we found that the maximum PC is greater than the critical PC. This study may serve for further technological progress with HTS.