Interaction between superconducting and magnetic rare-earth subsystems in RBa2Cu3O(9-delta)

The magnetic properties of rare-earth (RE) superconducting RBa2Cu3O(9-delta) (where R = Y, Gd, Ho, and Er) are investigated in the 5-300 K temperature range in magnetic fields up to 320 Oe. It is shown that both above and below Tc the RE subsystem is paramagnetic and is characterized by a weak antiferromagnetic exchange. The interaction between the RE and superconducting subsystems is shown to be small. Hc1 and Jc are estimated in the framework of a simple phenomenological model.