REVERSAL MECHANISMS IN SINTERED ND-FE-B

The magnetic viscosity, and the reversible and irreversible susceptibi lities of a sample of anisotropic sintered Nd-Fe-B have been measured starting from various initial magnetized states. It is shown that the heights of energy barriers preventing the reversal of the magnetizatio n in the grains depend on the initial magnetic state of the material. The change in energy barrier distribution is shown to be accompanied b y a change in the nature of the magnetization reversal process, which cannot be described solely in terms of simple model pinning mechanisms .