Barkhausen noise in nucleation-type hard magnetic materials

Abstract The Barkhausen effect was experimentally investigated in sintered NdFeB hard magnetic materials. We analyzed noise properties along different magnetization curves. The jumps are associated with the reversal of single grains or of groups of grains. The comparison of noise properties along different curves gives experimental support to the nucleation-type picture. Jump-size distributions follow a power law with critical exponent 1.2, and with exponential cutoff depending on magnetization curve considered. The maximum cutoff size is correlated to a microstructural limit due to the average grain size.