Structure, magnetic properties and magnetostriction in NdFe1.9 bulk nanocrystalline alloys

Bulk nanocrystalline NdFe1.9 cubic Laves alloy was synthesized by melt-spinning and subsequent high-pressure annealing. It was found that NdFe1.9 cubic Laves phase could not be obtained by annealing the as-spun amorphous ribbons at ambient pressure. In contrast, the sample annealed under high-pressure shows almost single cubic Laves phase with an average grain size about 30 nm. The temperature dependence of a.c. initial susceptibility exhibits an abnormal at 140 K, corresponding to the spin reorientation taking place from <1 1 0> to <1 0 0>. A low intrinsic coercivity of 25 Oe is observed at 300 K, indicating a tiny hysteresis loss at ambient temperature. The intrinsic coercivity increases to 3.9 kOe with decreasing temperature to 5 K, which can be associated with the narrow domain walls. The room-temperature magnetostriction was investigated using standard strain gauge technique.

► NdFe1.9 bulk nanocrystalline alloy with average grain size ∼30 nm was synthesized. ► The obtained nanostructure could be ascribed to the effect of high pressure. ► A low intrinsic coercivity of 25 Oe was observed at room temperature. ► The spin reorientation temperature and Curie temperature were determined. ► Provide an effective method of synthesizing RFe2 bulk nanocrystalline compounds.