Investigation on new material for high density recording media with high thermal stability

Abstract

This thesis investigated a novel exchange-coupled bilayers structure that used an antiferromagnetic layer to directly exchange-couple with a magnetic layer. A theoretical model for the proposed exchange-coupled bilayers structure was built up. Magnetization switching behaviors of such medium structure were calculated. To implement this new medium structure, an antiferromagnetic CoDy layer was chosen and sputtered on top of a CoCrPtB magnetic layer with perpendicular anisotropy. The exchange coupling in such medium structure was shown to be much higher than that in the AFC medium. The composition and thickness effects of CoDy layer in such medium structure were investigated systematically. It was found that the magnetic properties of the CoCrPtB layer were changed greatly through the exchange coupling with the CoDy layer. The exchange bias training effect was studied. The magnetization training effect was found for the exchange-coupled bilayers system, which was a new fundamental finding on the exchange-coupled bilayers structure.