Magnetic and superconducting properties of RBa 2Cu 3−xM xO y (RY, Nd, Gd, Dy and Er; M=Ni and Zn)

Abstract

The effects of Ni and Zn substitutions for Cu in RBa 2Cu 3O y (RY, Nd, Gd, Dy and Er) on the superconducting transition temperature T c and magnetic properties above T c have been investigated. In heavy rare earth compounds, the effects of the substitution on magnetic properties are not remarkable and the decrease rate of T c of them are almost same as that of Y compound. In Nd compound, however, the paramagnetic Curie temperature θ p is large and negative (∼ −30 K) in spite of its relatively small de Gennes factor and the substituent concentration dependence θ p and the decrease rate of T c are larger than those of heavy rare earth compounds