Thermomagnetic recording system employing a medium having high storage density and direct-overwrite capability as a result of along-track isocoercivity

A thermomagnetic recording system, comprising:

• a thermomagnetic recording medium having data tracks provided thereon;
• a heat source which raises temperature of a heated region of the medium from an ambient temperature to an operating temperature;
• and
• a magnetic assembly comprising a magnetic field source, which imposes a magnetic field upon an area of the medium including a portion of the heated region, and a magnetic field detector which senses a remanent magnetic moment of the medium over a substantially rectangular sensing region having longest dimension normal to the length of data tracks on the medium;
• wherein the medium comprises:
• a substrate;
• a barrier layer deposited on the substrate;
• a magnetizable recording layer deposited on the barrier layer, wherein the recording layer has a net magnetic moment and coercivity dependent upon temperature, such that the net magnetic moment is substantially zero at the ambient temperature and substantially different from zero in the heated region which is at an operating temperature, the coercivity decreases with temperature to zero at a Curie temperature which is substantially above the operating temperature, and the portion of the heated region which is exposed to the imposed magnetic field exhibits substantially constant coercivity along the length of the tracks;
• and
• a protective layer deposited on the recording layer.