"Magnetic design evolution in perpendicular magnetic recording media as revealed by resonant small angle x-ray scattering"

Tianhan Wang: Virat Mehta, Yoshihiro Ikeda, Hoa Do, Kentaro Takano, Sylvia Florez, Bruce D. Terris, Benny Wu, Catherine Graves, Michael Shu, Ramon Rick, Andreas Scherz, Joachim Stöhr and Olav Hellwig; Applied Physics Letters, 09/10/13.

Additional Authors: Virat Mehta, Yoshihiro Ikeda, Hoa Do, Kentaro Takano, Sylvia Florez, Bruce D. Terris, Benny Wu, Catherine Graves, Michael Shu, Ramon Rick, Andreas Scherz, Joachim Stöhr and Olav Hellwig

Abstract:

We analyze the magnetic design for different generations of perpendicular magnetic recording (PMR) media using resonant soft x-ray small angle x-ray scattering. This technique allows us to simultaneously extract in a single experiment the key structural and magnetic parameters, i.e., lateral structural grain and magnetic cluster sizes as well as their distributions. We find that earlier PMR media generations relied on an initial reduction in the magnetic cluster size down to the grain level of the high anisotropy granular base layer, while very recent media designs introduce more exchange decoupling also within the softer laterally continuous cap layer. We highlight that this recent development allows optimizing magnetic cluster size and magnetic cluster size distribution within the composite media system for maximum achievable area density, while keeping the structural grain size roughly constant.