A novel crystalline soft magnetic intermediate layer for perpendicular recording media

In order to improve the recording efficiency in current perpendicular recording media, it is important to reduce the distance from the head to soft underlayer. In this paper, a soft magnetic intermediate layer is proposed to partially replace the presently used Ru intermediate layer. The new soft magnetic intermediate layer serves two purposes, which are as follows: 1 to decrease the thickness of the nonmagnetic Ru intermediate layer by providing a proper crystalline texture and surface morphology for the optimal crystalline grain growth of the magnetic storage layer on top and 2 to act as an additional soft magnetic underlayer that is closer to the head air bearing surface to enhance the recording performance. The prototypes of the soft magnetic intermediate layer consists of CoIr:SiO2 /CoPt:SiO2 /NiW multilayer structure. CoIr and CoPt were chosen because both have the hcp structure but the opposite sign for K1. A zero effective magnetoanisotropy of a composite grain is accomplished by varying the thickness ratio of each layer of CoIr and CoPt. The developed multilayer film shows the hcp 00.2 orientation with a dome morphology for facilitating the growth of the top magnetic storage layer as well as soft magnetic properties K1=6.8 105 erg /cc . © 2009 American Institute of Physics. DOI: 10.1063/1.3079899