Marker for indicating degaussing of magnetic storage devices

摘要

A tag or marker applied to a magnetic digital information storage device undergoes a visually observable change when subjected to a magnetic field of preselected intensity to provide visual evidence that the storage device has been degaussed or otherwise subjected to a magnetic field. The tag or marker comprises microcapsules containing an encapsulated mixture of magnetic particle suspended in a suspending vehicle. The magnetic particles have first and second surfaces that provide a visually different appearance depending upon the orientation of the magnetic particles. Upon exposure to the magnetic field of preselected strength or intensity, the magnetic particles change orientation to provide the visual evidence of degaussing.