Pressure and Cr-Doping Effects of CdC_yNi₃

Abstract

The superconducting transition temperature (T c ) of CdC y Ni 3 was measured under different pressures. The T c increased at rates of 0.190 and 0.017 K/GPa for samples with y ≈ 0.93 and 0.96, respectively when the pressure was increased. The effect of the pressure on the y ≈ 0.93 sample is the largest among the antiperovskite superconductors. This result can be understood based on the difference between the bulk moduli of the antiperovskite superconductors, except for the y ≈ 0.96 sample. Cr-doped CdC y Ni 3-x Cr x was synthesized and the magnetic susceptibility was measured. The T c increased from 1.87 K at x = 0 to 4 K for x values of 0.7 and 0.8. This result probably arises from a reduction in the carrier concentration, not from the chemical pressure effect by Cr doping.