Effect of CrRu underlayer on the magnetic, recording, and thermal stability characteristics of CoCrPtTa thin film media

The effects of CrRu underlayers on the grain size, lattice match, magnetic, recording and thermal stability characteristics for CoCrPtTa thin film med ia are presented. CrRu10 and CrRu20 underlayer produced about 800-900 Oe hi gher coercivity compared to media with Cr underlayer. At 300 kfci recording density the CoCrPtTa/CrRu media has about 10-15% lower media noise and abo ut 1-1.5 dB higher SNR compared to the similar media with Cr underlayer. X- ray diffraction data suggest somewhat better lattice matching between the C oCrPtTa/CrRu media due to the addition of Ru to the Cr underlayer compared to CoCrPtTa/Cr media, The CoCrPtTa/CrRu media has an average grain size of 12 nm in comparison to the average grain size of 15 nm for the CoCrPtTa/Cr media. The thin film media with CrRu10 underlayer has smaller grain size bu t similar thermal stability performance compared to Cr underlayer.