Lorentz transmission electron microscopy study of micromagnetic structures in real computer hard disks

We have studied micromagnetic structures in real computer hard disks, with emphasis on magnetic vortices and ripples at bit-transition regions and track edges, using Lorentz transmission electron microscopy (LTEM). A combined dimpling and chemical etching was used to produce LTEM specimens of Co alloy/Cr with large, uniformly thin areas from the typical C/Co alloy/Cr/NiP/Al(substrate) hard disk structures.