Magnetic recording medium and method of making the same

摘要

A magnetic recording medium, and methods of making and reading the same, including on at least a portion of a substrate an irreversible recording layer which contains an irreversible recording material undergoing an irreversible change of saturation magnetization upon heating. The invention involves the steps of previously heating the irreversible recording layer to form an initial heated region in which a plurality of heated bars whose saturation magnetization has been irreversibly changed are arrayed in a bar code pattern, and converting unheated bars disposed between the heated bars into a heated state for changing the array pattern of heated bars, thereby recording the information.