| Popis: |
Solid solutions of RE(Ba2-xREx)Cu3O7+ delta (RE=Nd, Sm, Eu, Gd, Dy) for x=0 to x=0.5 have been investigated. X-ray and resistivity measurements show that there exists a solid solution region, through which the structure changes from orthorhombic to tetragonal and the superconducting properties are depressed. The solubility limits depend strongly on the size of the rare-earth ion, with the smallest (Dy) showing no appreciable solubility. The superconducting transition temperature versus x for all of the rare-earth-ion substitutions falls on a universal curve, indicating that the Ba sites are extremely ionic and magnetically isolated. |
