The crystal structure and magnetic properties of the rare-earth nickel (RNi) compounds

Abstract

The crystal structure of GdNi has been accurately determined and the lattice constants of eleven isomorphous rare-earth nickel (RNi) compounds, with the CrB type structure, measured. The magnetization of these compounds has been measured as a function of temperature in a field of 14.24 kOe. Saturation magnetization measurements were made at 4·2°K in fields up to 80 k0e. The effective paramagnetic moments agree excellently with the theoretical moments of free R 3+ ions. The Curie temperatures of the RNi compounds have been determined and compared with those of the RNi 2 and RNi 5 compounds. The spin moments appear ferromagnetically aligned parallel with the crystal b-axis, normal to the puckered sheets of R and Ni atoms comprising the crystal. A single crystal of SmNi exhibits a coercive force of 35 kOe at 1·4°K. The most important interatomic distances are Ni-Ni at 2·614, Gd-Ni at 2·903, 2·917 and 2·954 Å, and Gd-Gd at 3·588 and 3·631 Å. The smoothed volume change between LaNi and LuNi is −17 per cent.