Model of the magnetic properties of FePt granular media

We have used a Monte Carlo model of an interacting fine particle system to study the magnetic properties of FePt nanoparticle arrays. The model is capable of calculating the temperature dependence of the hysteresis loop and dc demagnetization remanence curves. We have made a detailed fit of the theo...

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Bibliographic Details
Published in:Journal of applied physics 2002-05, Vol.91 (10), p.6866-6868
Main Authors: Chantrell, R. W., Weller, D., Klemmer, T. J., Sun, S., Fullerton, E. E.
Format: Article
Language:English
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Summary:We have used a Monte Carlo model of an interacting fine particle system to study the magnetic properties of FePt nanoparticle arrays. The model is capable of calculating the temperature dependence of the hysteresis loop and dc demagnetization remanence curves. We have made a detailed fit of the theory to experimental data over the temperature range 10–350 K. The value of the best-fit anisotropy is K=2.35×107 erg/cc. This value is around one third the value expected for bulk FePt, possibly due to chemical disorder. The determination of K by application of Sharrock’s law to the temperature dependence of Hc gives a value of 7×107 erg/cc. It is shown that this arises from a breakdown of Sharrock’s law for systems containing a significant fraction of superparamagnetic particles.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.1447175