Crystal structure and magnetic properties of the off-stoichiometric compounds CeNi₃Cu₃ and CeNi₄Cu₂

The crystallographic properties of the compounds CeNi₃Cu₃ and CeNi₄Cu₂ have been investigated by time-of-flight neutron diffraction. A Rietveld profile refinement of the data shows that these compounds crystallize in the hexagonal TbCu₇-type structure and that Ni atoms have a greater preference as compared with Cu atoms for occupying the 2e dumb-bell site. A site preference of Cu atoms for the 2c sites is observed. Magnetic measurements made on these compounds show that the trivalent character of the Ce atoms increases with Cu concentration.