Microstructure and interphase magnetic coupling in Nd2Fe14B/alpha-Fe nanocomposites obtained by mechanical milling and short time annealing

The effects of short time annealing and soft phase pre-milling on the structural and magnetic properties of 6 h milled Nd2Fe14B/10wt% Fe magnetic nanocomposites were investigated. The X-ray diffraction peaks of Nd2Fe14B disappeared after milling due to crystal structure damage, this effect being more pronounced when using pre-milled Fe. After annealing, the characteristic peaks of Nd2Fe14B were restored with a limited growth of the α-Fe crystallites. The best exchange coupling was obtained for the samples which contain unmilled Fe as the soft phase. The maximum coercive field is 0.61 T. The samples containing pre-milled Fe have lower coercive field values, but show a higher remanence. The Nd2Fe14B/α-Fe exchange coupling is analysed.