Magnetic media patterning utilizing heat-induced phase transition

A patterned magnetic medium, comprising:

• (a) a substrate;
• and
• (b) a patterned magnetic recording layer on said substrate, said patterned magnetic recording layer having a Curie temperature (Tc) substantially above room temperature and a surface comprising a magnetic pattern formed therein by a process comprising the steps of:
• i. applying to the easy axis of said magnetic layer a first uniform magnetic field of a first direction and having sufficient strength to substantially uniformize the magnetic state of the magnetic layer by pre-alignment of the magnetic regions thereof;
• ii. applying to the magnetic layer a second uniform magnetic field of a second direction opposite to and having a strength less than that of said first magnetic field, said second strength of said second magnetic field being sufficient to alter the alignment of said magnetic regions of said magnetic layer when the latter is at a first, elevated temperature equal to or greater than Tc but insufficient to alter said magnetic regions of said magnetic layer when the latter is at a second, lower temperature below Tc;
• iii. selectively increasing the temperature of a patterned plurality of selected portions of the surface area of said magnetic layer to at least Tc for a desired interval while applying said second magnetic field to said magnetic layer, thereby selectively altering the magnetic alignment of said magnetic regions of said patterned plurality of selected portions of said magnetic layer;
• iv. terminating application of said second magnetic field to said magnetic layer after completion of step iii.;
• and
• v. cooling the patterned plurality of selected portions to a temperature below Tc.

A system for forming a magnetic data/information storage and retrieval medium having a patterned magnetic recording layer, comprising:

• a magnetic means for applying a uniform magnetic field of a desired direction to a magnetic recording layer having a Curie temperature (Tc) which is substantially above room temperature to place said magnetic layer in a particular magnetic state;
• and
• a means for forming a magnetic pattern in said magnetic layer by selectively increasing the temperature of a selected plurality of portions of a surface of said magnetic layer to at least Tc for a desired interval,
• wherein said magnetic means has sufficient strength to alter the magnetic state of said magnetic layer when the magnetic layer is at a first, elevated temperature at or above Tc, but insufficient to alter said magnetic state of said magnetic layer when the magnetic layer is at a second, lower temperature below Tc.