Magnetic properties of the high-Tcsuperconductors RBa2Cu3O9-δ(R=Gd, Dy, Er)

Abstract
Magnetic properties of RBa2Cu3O9- delta with R=Y, Gd, Dy, ER have been measured for 4.2 K<T<300 K and magnetic fields up to 7 T. They exhibit a superconductive transition around 91 K, above which temperature the magnetisation can be described by a Curie-Weiss law. The magnetic and superconductive properties develop independently below the phase transition. Magnetic hysteresis is prominent at low temperatures (T<or approximately=25 K) and varies for different samples. Estimates for critical densities are given.