System and method for overwriteable magneto-optical recording
AssigneeIBM Corporation
InventorTomoko Ohtsuki
Life of this patent
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Abstract
A system and method for overwriteable magento-optical recording comprises a medium having a data layer and a reference layer. The medium is heated with a laser pulse of short duration which causes a temperature gradient between the data layer and the reference layer. The temperature of the data layer becomes greater than the Curie temperature of the data layer, but the reference layer remains at a temperature below the Curie temperature of the data layer. The magnetic orientation of the reference layer thus remains unchanged and the data layer will orient itself in the same direction as the reference layer. It is therefore not necessary that the Curie temperature of the reference layer be greater than that of the data layer.
Claims24
A data recording system comprising:
- a recording medium having a data layer and a reference layer;
- an electromagnetic source for directing an electromagnetic beam at the recording medium;
- a pulse means connected to the electromagnetic source for causing the electromagnetic source to pulse for a first period of time and a second period of time, the first period of time of short enough duration to create a temperature differential between the data layer and the reference layer such that the data layer is heated to a first temperature at least equal to the Curie temperature of the data layer and the reference layer is heated to a second temperature less than the Curie temperature of the data layer, the second period of time being sufficient to heat the reference layer to a temperature at least equal to the Curie temperature of the reference layer;
- and
- a magnetic source positioned proximate the medium for providing a magnetic field.
A method for magneto-optical recording comprising the steps of:
- passing a recording medium proximate a magnetic source, the medium having a first and a second layer, the first layer having a coercive force greater than the coercive force of the second layer such that the magnetic source changes the magnetic orientation of the second layer in a first direction, but does not change the magnetic orientation of the first layer;
- and
- directing an electromagnetic beam at a selected first portion of the recording medium for a first period of time, said first period of time of short enough duration to create a temperature differential between the first and second layers such that the first layer is heated to a first temperature at least equal to the Curie temperature of the first layer, and the second layer is heated to a temperature less than the Curie temperature of the first layer, such that the selected first portion of the first layer has its magnetic orientation aligned with the magnetic orientation of the selected first portion of the second layer.
Dependencies are inferred from the claim text.