Computer calculation of the Lorentz microscopy image and magnetic domain structure of weakly ordered FePt:C thin film

A computer calculation technique of Lorentz microscopy image was developed and was applied to the analysis of the Lorentz microscopy image and magnetic domain structure of a weakly ordered FePt:C thin film for recording media. The magnetic domain structure was, at the as-deposited random state, a vortex network structure and evolved into the islandlike elongated reverse domain structure at the dc-demagnetization state, via a featherlike ripple structure at the remanent state. The magnetization reversal occurred not by the domain wall motion but by the local magnetization rotation to form a series of local vortices leading to the formation of reverse domains. © 2007 American Institute of Physics. DOI: 10.1063/1.2746078