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Media with excellent signal to noise properties and adequate high temperature thermal stability have been developed for over 20 Gbit/in2 recording. The media are fabricated by dc magnetron sputtering onto textured NiP films on Al-Mg substrates. The magnetic layer is a CoCr-based quaternary alloy with (11.0) preferred orientation on a Cr alloy  underlayer. The average grain diameter has been reduced to an average of <10 nm. TEM-EDX studies revealed that Cr segregation has been enhanced compared to a previous CoCrPtTa media used for 15 Gbit/in2 recording resulting in improved Co to Cr core composition and increased grain boundary Cr content. Spinstand measurements of the thermal decay after annealing at 65°C indicate sufficient thermal stability at 400 kfci for media with Mrδ>0.3 memu/cm2 consistent with magnetometry measurements.