Magnetic and structural behaviour of Nd2Fe14B/alpha-Fe and (NdDy)(2)Fe14B/alpha-Fe obtained by mechanical milling and annealing

International audienceTwo type of nanocomposite Nd2Fe14B+10 wt % alpha-Fe and (Nd0.92Dy0.08)(2)Fe14B+22 wt % a-Fe were prepared by high energy ball milling and subsequent annealing under high vacuum at different temperatures and annealing times. X-ray diffraction followed by electron microscopy were used to evidenced the evolution of the structure and microstructure of the samples. The width of the diffraction peaks of the hard magnetic phase increases with milling times and disappears after 12 h of milling. The remanent magnetisation, the coercive field and the exchange coupling between the hard and the soft magnetic phases were deduced from room temperature magnetic hysteresis loops, performed in magnetic fields up to 10 T