Superconductivity, long-range magnetic order and crystalline-electric field effects in ternary rare earth compounds

Results of an extensive calorimetric investigation of ternary are earth compounds such as RERh4B4 and RE12Mo6S8 and related pseudoternary systems was undertaken to study the competing mechanisms o superconductivity and magnetism. Heat capacity data were collected in zero and various applied magnetic fields for LuRh4B4 and in zero field for YRh4B4. A modified Debye model as well as a molecular crystal model were employed to describe the normal state data. Various superconducting and normal state parameters were derived. Spike-shaped features superimposed on top of a broader anomaly in the heat capacity of ErRh4B4 and Ho12Mo6S8 were observed at reentrant transitions, and the effects of external magnetic fields on this reentrant transition were investigated. Pronounced discontinuities in the specific heat at the magnetic ordering temperatures were apparent for the RERh4B4 compounds where RE = Gd,Tb,Dy, and Ho, and the contribution of ferromagnetic transitions to the specific heats of these compounds is discussed. Phase diagrams were constructed which delineate the paramagnetic, superconductivity, magnetically ordered and normal, and magnetically ordered and superconductivity regions. Crystal field effects were also investigated for both types of compounds