Recording Behavior of Exchange Coupled Composite Media

The recording behavior of exchange coupled composite (ECC) media is investigated. It is found experimentally that the change of the written track width is less pronounced as a function of linear density when the write-ability is controlled by varying the vertical exchange coupling between the various layers in the medium stack as opposed to varying the lateral exchange coupling between the grains. The results are explained using a simple three-spin model which captures the essential physics. It is pointed out that the traditional concept of an effective field that separates out the field angle effect does not apply to the recording process of ECC media.