Superconductivity in ThT₂B₂C and Strong Magnetismin UT₂B₂C (T=Ni, Rh and Pt)

Abstract

We have synthesized quaternary compounds UT 2 B 2 C (T=Ni and Rh) and ThT 2 B 2 C (T=Ni, Rh and Pt) which crystallize in the LuNi 2 B 2 C-type structure. The uranium compounds with 5f electrons exhibit strong magnetism; UNi 2 B 2 C orders antiferromagnetically at 218 K and URh 2 B 2 C orders ferromagnetically at 185 K. In contrast, the nonmagnetic analogues ThNi 2 B 2 C and ThPt 2 B 2 C undergo superconducting transitions at 6.5 and 6.7 K, respectively.