Magnetic properties of a typical weak-link system, ceramic YBa_2Cu_3O_(7-δ), have been investigated in order to clarify the inter-grain superconducting ordering. Paramagnetic Meissner behavior is observed in the field-cooled magnetization of the ceramics below the inter-grain transition temperature. The result suggests that the paramagnetic Meissner effect is one of the inter-grain properties and is due to the spontaneous orbital currents in a Josephson network with π-junctions.
展开▼
