Spin‐polarized secondary electron microscope images of tracks of magnetic domains, written in Co62.5Ni30Cr7.5thin‐film longitudinal recording media, are presented as a function of write current. The corresponding modulation noise measurements are also presented for this sample. We observe that the magnetic microstructure visible in the images can be correlated with the modulation noise in each region of write current investigated. Explanations for the possible origins of this microstructure are presented.