Paramagnetism of superconducting ceramics
Panyukov S. V., Zaikin A. D.
The interaction between spontaneous current loops (orbital magnetic moments) induced by weak links with negative coupling energies (the junctions) can cause paramagnetism in granular high-temperature superconductors. It is shown that at a certain concentration of π junctions the system consists of infinite, percolating, superconducting clusters and normal regions with a frozen-in magnetic field and ordered orbital magnetic moments.