Structural analysis of the hard ferromagnetic phase observed in quenched Nd-Fe alloys of hyper-eutectic composition

Recently, a new hard ferromagnetic phase has been reported in quenched Nd sub 100--x Fe sub x with hyper-eutectic compositions (x < 25) This phase, labelled A sub 1 in the literature, has a coercivity of 2-5 kOe at room temperature (depending on the quenching rate) and a Curie temperature of 245 deg C. It is not possible to obtain this phase as a pure phase, and therefore only indirect analysis of its properties can be carried out. Recently, the analysis of the basic magnetic properties of this phase (i.e. magnetization and anisotropy) has been performed and an estimation of its composition has been deduced from the combination of Mossbauer spectroscopy and magnetic measurements. A structural analysis of this ill-defined phase was carried out by means of neutron diffraction and transmission electron microscopy (TEM).