Preparation and the physical properties of antiperovskite-type compounds Cd_1-xIn_xNNi₃ (0≤x≤0.2) and Cd_1-yCu_yNNi₃ (0≤y≤0.2)

Two series of Cd_1-xIn_xNNi₃ (0≤x≤0.2) and Cd_1-yCu_yNNi₃ (0≤y≤0.2) samples were prepared from CdO, In₂O₃, CuO, and nickel powders under NH₃ atmosphere at 773 K. The structural and physical properties were investigated by means of X-ray powder diffraction temperature-dependent resistivity and magnetic measurements. X-ray powder diffraction results showed that the Cd_1-xIn_xNNi₃ and Cd_1-yCu_yNNi₃ compounds have a typical antiperovskite structure, and the CdNNi₃, Cd_0.9In_0.1NNi₃, and Cd_0.9Cu_0.1NNi₃ compounds show metallic temperature-dependent resistivity and exhibit a Fermi liquid behavior at low temperature. In contrast to the paramagnetism previously reported, the CdNNi₃ sample exhibits very soft and weak ferromagnetism, and no superconductivity was found in the Cd_1-xIn_xNNi₃ and Cd_1-yCu_yNNi₃ samples down to 2 K. Each sample exhibited very soft and weak ferromagnetism, and the temperature dependence of the magnetization of the Cd_1-xIn_xNNi₃ and Cd_1-yCu_yNNi₃ samples can be well fitted to the combination of a Bloch term and a Curie-Weiss term.