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 B_T 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 B_T 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 B_T. The optimization of the applied field B2 and the lowering of the operating temperature T2 at the second stage are also effective to enhance B_T. The flux intrusion and the flux trap are effectively promoted at low temperatures by the existence of already trapped fluxes during the first stage.