Investigations on nano-structured perpendicular recording media for high density data storage

The recording performance of CoCrPt–SiO2 based perpendicular recording media had been enhanced using two approaches. The first approach involved the use of dual-Ru intermediate layers to obtain both good preferred c-axis orientation as well as better macro-magnetic properties. The bottom Ru layer, deposited under a higher mobility condition, helped to achieve a good crystalline texture. The upper Ru layer deposited under a lower mobility condition helped in promoting isolated grain morphology which lead to an improved coercivity, large negative nucleation field, etc. Signal-to-noise ratio (SNR) improvement was obtained for media with dual-Ru intermediate layer in comparison with that of single intermediate layer media (single-Ru media). The second approach involved the use of dual recording layers to obtain a small grain size and a high thermal stability. In this approach, the bottom layer deposited with large oxygen concentration helped to achieve small grain size. The top layer deposited with less oxygen helped to provide thermal stability. In brief, these dual layered structures provide solutions for high-density perpendicular recording.