MAGNETIC AND CRYSTAL-STRUCTURE OF THE NOVEL COMPOUND ND3FE29-XTIX

The structure of the compound previously reported as Nd2Fe 19-xTix has been solved by powder neutron diffraction, which reveals a monoclinic cell and a stoichiometry of Nd3Fe 29-xTix (x=1.24) and two formula units per unit cell. This low symmetry, and the large number of crystallographically unique sites (17), lead to a wide range of Fe - Fe bond lengths (from 2.36 to 3.01 Å) in a nearly continuous band. The phase forms through the replacement of two-fifths of the rare earths in the RFe5 phase by Fe-Fe dumbbells. The magnetic moments at room temperature lie along the monoclinic a axis with an average iron moment of 1.05 μB, while the magnetic moments at 12.5 K lie in the a-b plane with an average iron moment of about 1.36 μB.