Patent ID: 6377414
Filing Date: 2002-04-23
Classification: B82Y,G11B

Abstract:
A method of forming a magnetic pattern in a magnetic data/information storage and retrieval medium, comprising the steps of:(a) providing a magnetic medium including a magnetic recording layer having a surface, said magnetic recording layer comprising a magnetic material having a Curie temperature (Tc) substantially above room temperature; (b) applying to said magnetic layer a first uniform magnetic field of a first direction and strength sufficient to substantially uniformize the magnetic state thereof; (c) applying to said magnetic layer a second uniform magnetic field of a second direction opposite to and of lesser strength than that of said first magnetic field, said strength of said second magnetic field being sufficient to alter the magnetic state 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 state of said magnetic layer when the latter is at a second, lower temperature below Tc; (d) selectively increasing the temperature of at least one selected portion 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 state of said at least one selected portion of said magnetic layer; (e) terminating application of said second magnetic field to said magnetic layer after completion of step (d); and (f) cooling the at least one selected portion of the magnetic layer to a temperature below Tc.