The aim of this proposal is to understand the initial propagation of a sharp magnetic soliton after nucleation in tall synthetic ferrimagnetic structures (with six and eight magnetic layers). This proposal builds on the insights we gained from previous measurements on four layer stacks. We propose to investigate a region of propagation indicated by magnetoresistance measurements. Bulk measurements are unable to distinguish between the different possible states as the total magnetisation remains the same in each case. Only PNR will be able to distinguish between alternative models.