Synthesis and the physical properties of the single crystals of a new quaternary compound ErRh₂B₂C using molten copper as a flux

The single crystals of a. new quaternary compound ErRh₂B₂C have been obtained as thin plates in an atmosphere of helium by the flux method using molten copper. The single crystals show golden-colored luster and the maximum size obtained is about 1.0 × 1.0 × 0.02 mm³. This compound belongs to a tetragonal system and seems to be a derivative of ThCr₂Si₂ type; lattice parameter: a=0.36848 (2) nm, c=1.05520 (3) nm, V=1.4327 × 10^-28 m³ and Z=2. The electrical resistivity parallel to the a-b plane decreases monotonically with decreasing temperature, but no superconductivity is observed down to 1.5K. The residual resistivity ratio, ρ(273 K)/ρ(1.5 K), is 1.38. Similar type new compounds of RRh₂B₂C were obtained for R=La-Er (except Eu and Tm) and Y by arc-melting synthetic method.