Importance of initial “M-shaped” trapped field profile in a two-stage pulse field magnetization (MMPSC) method

The influence of a shape of a trapped field distribution at a first stage on the final trapped field BT at a second stage has been investigated in the two-stage pulse field magnetization technique named as a modified multi-pulse technique with stepwise cooling (MMPSC). The final trapped field BT strongly depends on the shape and the strength of the trapped field at the first stage. The “M-shaped” profile with a moderate number of magnetic fluxes at the first stage maximizes the final BT. The optimization of the applied field B2 and the lowering of the operating temperature T2 at the second stage are also effective to enhance BT. The flux intrusion and the flux trap are effectively promoted at low temperatures by the existence of already trapped fluxes during the first stage.