Magnetic Properties and Recording Characteristics of High Magnetization Exchange-Coupled Double-Layer TbFeCo for Magnetic Flux Reading Optical Recording

Abstract

The magnetic properties and recording characteristics of exchange-coupled double-layer (ECDL) disks consisting of a transition metal-rich TbFeCo readout layer with high magnetization and a recording layer were studied for magnetic flux reading optical recording. The effective coercivity of ECDL with rare-earth (recording)/transition metal-rich (readout) films could be greatly enhanced from 1.7 to 7.6 kOe through exchange coupling between two active layers. Moreover, ECDL disks possess a lower recording bias field (100 Oe) and a lower onset field (-150 Oe) for thermomagnetic writing. The enhanced effective coercivity was explained by the Kobayashi model, and the lower bias field and onset field of ECDL disks were analyzed by the modified nucleation field model. The ECDL disks with magnetization over 300 emu/cm3, high stability and low recording bias field are potentially applicable for magnetic flux readout toward high density recording at a high writing rate.