Micromagnetic Simulation of Recording Media and Magnetoresistive Heads

Kazuetsu YOSHIDA  Yasutaro UESAKA  Kazuhisa FUJIMOTO  

IEICE TRANSACTIONS on Electronics   Vol.E78-C   No.11   pp.1509-1516
Publication Date: 1995/11/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Ultra High Density Information Storage Technologies)
micromagnetic simulation,  thin-film recording media,  magnetoresistive heads,  

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A three-dimensional micromagnetic simulation using the Landau-Lifshitz-Gilbert equation was performed for thin-film magnetic recording media and magnetoresistive (MR) heads with soft adjacent layers (SAL). For recording media the simulation results for magnetization curves and media noise were compared with the results of experiments. Although the media model needs to be improved, the qualitative agreement between simulation results and experimental results shows that this micromagnetic simulation can be a useful tool for analyzing and predicting magnetic properties and recording characteristics. This work also showed that media noise is influenced by magnetostatic interaction, and that the decrease of the magnetostatic interaction is favorable for obtaining a high signal-to-noise ratio. For an MR head the output obtained with a nonuniform sense current distribution is similar to the output obtained with uniform sense current distribution for both low and high anisotropy fields (Hk=2 Oe and 10 Oe) SAL. With the low Hk SAL, however, the asymmetry of the output obtained for nonuniform sense current differs from the asymmetry obtained for uniform sense current; the difference is due to a magnetization vortex in a biased state in the SAL. With the high Hk SAL, the difference between the asymmetry obtained for nonuniform sense current and the one obtained for uniform sense current is not large; no vortices are found in the SAL at the biased state.