Design of laminated antiferromagnetically coupled media for beyond 100 Gb/in ² areal density

In this report, we will present our experimental and micromagnetic simulation studies to show that laminated antiferromagnetically coupled media has potentials to push the areal density beyond 100 Gbit/in ². Exchange coupling constant as high as 0.32 erg/cm ² has been obtained for basic two layer configuration by inserting an ultrathin Co interface layer between CoCrPtB and Ru layers, which is 3-4 times higher than the reported values in literature. This technique improved the thermal stability factor by more than 40%. A type of sandwich three-layer configuration for the antiferromagnetic coupled media is proposed which may double the antiferromagnetic coupling effect for the recording CoCrPtB layer. It also can further reduce the M _rt value (less than 0.2 memu/cm ²) while keeping high thermal stability that may be preferred for future application once extreme high sensitivity read head appears.