Compositionally separated microstructure of Co-Cr films prepared by electron-cyclotron-resonance plasma sputtering

Compositional separation (CS) has been observed to occur in Co-Cr based alloy thin films grown at elevated substrate temperatures. This CS produces fine Co-enriched regions within grains, which are expected to give a magnetic microstructure suitable for high-density recording. We studied the compositional microstructure in Co-Cr films grown by electron-cyclotron-resonance plasma (ECR) sputtering with a view to reducing media noise and increasing recording density. ECR sputtering produced fine grains which supported particularly small and closely packed Co-enriched regions (less than 5 nm spacing) at elevated substrate temperature. This compositional microstructure is finer than that of RF-sputtered Co-Cr films. ECR sputtering simultaneously improves the magnetic properties and refines the compositional microstructure.