LOW-TEMPERATURE STRUCTURES OF THE ER2FE14B FERROMAGNETIC COMPOUND

Ferromagnetic compounds of Nd2Fe14B-type exhibit the large magneto cry stalline anisotropy of the type of rare-earth element (R) combined wit h that of iron. These competing anisotropies induce spin rotations and lower symmetry (from tetragonal space group P4(2)/mnm) when the tempe rature is decreasing In a previous study [1,2], it was evidenced that Ho2Fe14B and Nd2Fe14B exhibit continuous transformations of the magnet ic and crystallographic structures from the high-temperature tetragona l and uniaxial structure to the monoclinic Cm space group with a cante d magnetic arrangement. At 50 degrees C, Er2Fe14B exhibits a magnetisa tion rotation from the c- to the a-axis. Neutron diffraction measureme nts (D9 ILL) were performed recently and the refined structure (by usi ng MXD program [3]) is described in a orthorhombic symmetry.