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 0018-9464Full text available as:
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).
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|Keywords:||activation volume, CoPtCr-SiO2, fluctuation field, magneto-optic Kerr effect (MOKE), perpendicular recording media, thermal activation, TIME-DEPENDENCE, FIELDS|
|Academic Units:||The University of York > Physics (York)|
|Depositing User:||Repository Officer|
|Date Deposited:||15 Dec 2006|
|Last Modified:||17 Oct 2013 14:21|