Effect of Grain Size Distribution on the Performance of Perpendicular Recording Media

• Published in: IEEE transactions on magnetics Vol. 43; no. 3; pp. 955 - 967
• Main Author: Miles, J.J.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-03-2007; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Autocorrelation; Clusters; Computer simulation; Couplings; Cross-disciplinary physics: materials science; rheology; Disorders; Exact sciences and technology; Grain size; Grains; Hard disks; Jitter; Magnetic disk recording; Magnetism; Magnetostatics; Materials science; Media; micromagnetic modeling; Micromagnetics; Microstructure; Noise shaping; Other topics in materials science; Perpendicular magnetic recording; perpendicular recording; Physics; recording media; Shape; Studies; Grain size; Magnetic disk recording; perpendicular recording; Disks; Recording material; Modelling; recording media; Microstructure; micromagnetic modeling; Magnetic recording; Magnetic properties
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2006.888354

Micromagnetic simulations of perpendicular recording in hard disk storage media have been performed with model media of variable microstructural disorder. Simulations indicate that increasing disorder, either due to size and shape distribution or due to disordered packing, decreases signal and increases noise. The mechanism observed in the model is that, in a disordered microstructure, there is a distribution of magnetostatic and exchange coupling between grains that acts to create clusters of grains that act collectively. These clusters increase the auto-correlation function of the spatial distribution of magnetization that is a measure of the magnetic feature size. Consequently, the transition width between recorded bits increases and the position variation of the transition locations (jitter) increases, so that signal-to-noise ratio (SNR) falls. The results suggest that microstructurally ordered media will exhibit higher performance, and that such effects may ultimately demand the use of self-assembled or patterned media with regular packing and very narrow size distribution