Magnetic properties of the ternary hydrides of Nd6Mn23 and Sm6Mn23

The intermetallic compounds Nd6Mn23 and Sm6Mn23 and their ternary hydrides were studied by X-ray diffraction. The crystal structure (Th6Mn23 type) is preserved after hydrogen absorption. From the change in lattice constants a volume increase of about 14% was deduced. The temperature dependence of the magnetization of Nd6Mn23, Sm6Mn23 and their hydrides was studied in the range 4–500 K. The uncharged compounds have magnetic ordering temperatures above 400 K while in the hydrides magnetic ordering occurs close to 200 K. Indications were obtained of a substantial weakening of the magnetic coupling between the rare earth and manganese sublattice magnetization.