Reversible magnetization behavior and exchange coupling in two-phase NdFeB melt spun ribbons

The present paper presents some aspects related to the magnetic features of some two-phase αFe/Nd2Fe14B melt spun ribbons: Nd4Fe86CuNb3B6 and Nd8Fe77Co5CuNb3B6 with the volume ratio of αFe soft magnetic phase to Nd2Fe14B hard magnetic phase of 28 and 71%, respectively, for the two investigated compositions. With decreasing the volume ratio of the hard magnetic component, the reversible magnetization behavior is accentuated (recoil relative permeability μrel rec increases) and remanence becomes more sensitive to microstructure. Exchange magnetic interactions are preponderant in Nd8Fe77Co5CuNb3B6 samples while in Nd4Fe86CuNb3B6, the dipolar type of interactions predominates at the investigated annealing conditions.