Study of superconductivity and antiferromagnetism in La_2-xNd_xRh₃Si₅ system

Abstract

It is well-known that the ternary rare earth silicides of the type R₂Fe₃Si₅ exhibit interesting superconducting and magnetic properties. Unlike R₂Fe₃Si₅ which forms in the tetragonal (space group P4/mnc) structure, R₂Fe₃Si₅ forms in the orthorhombic (Ibram or Iba2) structure. In this work, we establish the bulk superconductivity (T_c = 4.4 K) and bulk antiferromagnetism (T_N = 2.7 K) in La₂Rh₃Si₅ and Nd₂Rh₃Si₅, respectively, from resistivity, susceptibility and heat-capacity studies. The heat-capacity data of Nd₂Rh₃Si₅ reveal significant presence of crystal-field contributions. These results are compared with the heat-capacity study of Gd₂Rh₃Si₅ which shows bulk antiferromagnetic ordering below 8.5 K. We have also analyzed the variation of T_c with Nd substitution in the La_2-xNd_xRh₃Si₅ system.