Crystal structures of PrAlxGe2-x compounds

New intermetallic compounds R3Fe28Ta (R=Gd, Tb, Y) and their related hydrides and carbides were successfully stabilised with the monoclinic structure of the Nd3Fe29-xTix type. Insertion of hydrogen and carbon atoms up to about 8 and 4, respectively, induce an increase of the lattice parameters and of the Curie temperature. An analysis of the magnetisation versus the applied magnetic field using oriented samples was made for Tb3Fe28Ta and its hydride and carbide. Changes of the easy axis direction as dependent on temperature and the nature of the inserted element were observed.