Interplay of superconductivity and magnetism in the single crystals of Er1-xTbxNi2B2C

The measurements of temperature-dependent resistivity rho(T) and magnetization M(T) are carried out for the single crystals of Er1-xTbxNi2B2C (x=0.0, 0.1, 0.2, 0.25, 0.3, 0.35, 0.4, 0.6, 0.7, 0.8, 0.9, and 1.0) in order to study the superconductivity, magnetism, and their interplay in the temperature range of 2 Kless than or equal toTless than or equal to20 K. From the analysis of the rho(T) and M(T) data, the superconducting (T-c), antiferromagnetic (T-N), and weak ferromagnetic (T-WF), transition temperatures are derived and represented in terms of De Gennes (DG) factor. It is found that the T-c is suppressed with increasing Tb concentration and a crossover for T-c<T-N occurs at x=0.2. T-c variation follows well the DG scaling even when T-c<T-N. The T-N is almost independent of temperature at T≈6 K in the Er-rich side of the compounds (x≤0.4) and follows DG scaling based on the Ruderman-Kittel-Kasuya-Yosida interaction in Tb-rich side (x≥0.6). The T-WF also shows distinct behaviors in a Er- and Tb-rich region. The observed superconductivity, AF-ordered state, and weak ferromagnetic state are found to be closely correlated and will be discussed based on the magnetic interactions between Er and Tb elements. (C) 2003 American Institute of Physics.