Magnetic properties of large-scaled MnBi bulk magnets

Abstract We investigated the magnetic properties of large, compacted, sintered MnBi bulk magnets with dimensions of 20.3 × 15.3 × 10.3 mm 3 . To obtain a high content of the low-temperature-phase (LTP) of MnBi in the precursor powders, a new process was implemented and produced about 98 wt% of LTP. To improve the coercive field of MnBi, particle sizes were controlled using different milling techniques. The dependence of magnetic properties of the bulk magnets on the particle size was analyzed. The highest maximum energy product, ( BH ) max , obtained among our samples was 7.3 MGOe. This is the first report of demonstrating high performance in large-sized MnBi bulk magnets.