PHENOMENOLOGICAL INTERPRETATION OF SUPERCONDUCTIVITY AND MAGNETISM OF HO(1-X)DYXNI2B2C

Abstract

The coexistence of the superconductivity and magnetism in the Ho1-xDyxNi2B2C is studied by using Ginzburg-Laudau theory. This alloy shows the coexistence and complex interplay of superconducting and magnetic order. We propose a phenomenological model which includes two magnetic and two superconducting order parameters accounting for the multiband structure of this material. We describe phenomenologically the magnetic fluctuations and order and demonstrate that they lead to anomalous behavior of the upper critical field. The doping dependence of T-c in Ho1-xDyxNi2B2C showing a reentrance behavior is analyzed yielding very good agreement with experimental data.