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Incomplete magnetization switching may take place between two recorded transitions in perpendicular magnetic recording. These write process issues were studied with a micromagnetic model. The relatively poor effective field from the central part of the perpendicular writer is unable to reverse the media grains properly. Consequently, media dc noise will increase as the incomplete switching becomes more severe. An expression for the effective field heff was proposed to easily discover those cases. The incompletely switched magnetization observed in the static footprint could also be partially transferred into the dynamic write process. The calculated media signal-to-noise ratio on a pseudorandom sequence could be reduced by as much as 3 dB (compared to the fully switched case). On the other hand, transition quality does not become worse with a smaller heff. This insensitivity to the transition quality was caused by the magnetostatic field from the opposite magnetization polarity on the other side of the recorded bit. [ABSTRACT FROM AUTHOR]

A scaling technique is developed to predict micromagnetic properties of magnetic materials subject to thermal fluctuations over long time scales. This theory, based on the equivalence of time and temperature for thermally activated processes, is tested by predicting hysteresis loops for two different thin film magnetic recording media. A comparison to directly calculated values and to experimental hysteresis loop results shows that important features such as the coercivity are predicted with less than 1% error. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]