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Activation volumes in CoPtCr-SiO2 perpendicular recording media

Inaba, Y, Shimatsu, T, Muraoka, H, Dutson, J D and O'Grady, K (2005) Activation volumes in CoPtCr-SiO2 perpendicular recording media. IEEE Transactions on Magnetics. pp. 3130-3132. ISSN 1941-0069

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CoPtCr-SiO2 perpendicular recording media with varying levels of SiO2 were examined by two different methods to determine the activation volume. The first is based on the sweep-rate dependence of the remanence coercivity using Sharrock's equation. The second is based on the measurement of the fluctuation field from time-dependence data, determined using a magneto-optical Kerr effect (MOKE) magnetometer. The values of V-act measured at the coercivity for both methods are almost the same, with the fluctuation field and activation volumes increasing with the SiO2 content. The difference between V-act and the grain volume measured directly from bright-field TEM images decreases as the SiO2 content increases due to the reduction of intergranular exchange coupling. The experimental results indicate that values of V-act obtained from single- and double-layered media are consistent. It was also found that the coercivity and normalized hysteresis loop slope at coercivity varied with SiO2 content, with the coercivity peaking at 8 at % SiO2 (nearly 26 vol% SiO2).

Item Type: Article
Copyright, Publisher and Additional Information: © 2005 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: activation volume,CoPtCr-SiO2,fluctuation field,magneto-optic Kerr effect (MOKE),perpendicular recording media,thermal activation,TIME-DEPENDENCE,FIELDS
Institution: The University of York
Academic Units: The University of York > Physics (York)
Depositing User: Repository Officer
Date Deposited: 15 Dec 2006
Last Modified: 11 Jul 2016 06:36
Published Version: http://dx.doi.org/10.1109/TMAG.2005.854850
Status: Published
Refereed: Yes
URI: http://eprints.whiterose.ac.uk/id/eprint/1824

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