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Time dependence in perpendicular media with a soft underlayer

Dutson, J D, Wu, J, O'Grady, K, Woolsey, N C, Kubota, Y and Platt, C L (2004) Time dependence in perpendicular media with a soft underlayer. IEEE Transactions on Magnetics. pp. 2504-2506. ISSN 1941-0069

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Abstract

In this paper we describe measurements of magnetic viscosity or time dependence in magnetic thin films suitable for use as perpendicular recording media. Generally, such effects cannot be measured using conventional magnetometry techniques due to the presence of a thin (0.1 mum) soft underlayer (SUL) in the media necessary to focus the head field. To achieve our results we have developed an ultrastable MOKE magnetometer, the construction of which is described. This has enabled us to measure nominally identical films with and without the presence of the SUL. We find that the presence of the SUL narrows the energy barrier distribution in the perpendicular film increasing the nucleation field (H-n), reducing the coercivity (H-c) and results in an increase in the squareness of the loop. This in turn results in an increase in the magnitude of the viscosity in the region of the H-c but that the range of fields over which the viscosity occurs is reduced.

Item Type: Article
Copyright, Publisher and Additional Information: Copyright © 2004 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
Keywords: magnetic viscosity, MOKE magnetometer, perpendicular media, RECORDING MEDIA, SYSTEMS, VOLUMES
Institution: The University of York
Academic Units: The University of York > Physics (York)
Depositing User: Sherpa Assistant
Date Deposited: 16 Sep 2005
Last Modified: 14 Oct 2014 12:17
Published Version: http://dx.doi.org/10.1109/TMAG.2004.832259
Status: Published
Refereed: Yes
Related URLs:
URI: http://eprints.whiterose.ac.uk/id/eprint/650

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