CeRu₂ and ZrV₂: Two interesting C15 Laves-phase superconductors

Abstract

We present new results on the electrical and magnetic properties of the two well known Laves phase superconductors CeRu₂ and ZrV₂. While the magnetization against field behaviour of ZrV₂ resembles that of a conventional type II superconductor, the magnetization of CeRu₂ decreases sharply when its superconductivity is suppressed by an applied field. Furthermore, the magnetic susceptibility of CeRu₂ in the superconductivity state is distinctly more paramagnetic than in the normal state. These results suggest that CeRu₂ is an example of an extreme type II superconductor having a paramagnetic mixed state as discussed by Hake in 1967. The effects of alloying with magnetic elements, on both the normal and the superconducting states of these two compounds, are also discussed.