Studia Geophysica et Geodaetica

, Volume 49, Issue 2, pp 163–176 | Cite as

A Monte Carlo investigation of the representation of thermally activated single-domain particles within the Day plot

  • D. Heslop


Hysteresis based measurements are a standard part of many rock magnetic investigations. Whilst they provide information on the various magnetic minerals present in a natural sample they can also offer an insight into the domain state of the grains. The most commonly employed method to derive such structural information from hysteresis measurements is the Day plot, which employs ratios of different parameters to demarcate the possible domain states. Numerous experimental and modelling investigations have demonstrated that interpretation of the Day plot is not a simple task because the position at which an assemblage of magnetic grains plots within the space of the diagram is not solely a function of domain state. Here two mechanisms that appear to influence the Day plot are investigated. It is well known that thermal activation of an assemblage has the effect of randomising the magnetisation of grains until at sufficiently high temperatures they become superparamagnetic. A collection of Monte Carlo simulations for uniaxial, single-domain, Stoner-Wohlfarth (SW) grains with atomic moments that rotate coherently (Stoner and Wohlfarth, 1948), are utilised to demonstrate that the expression of this process could be easily misinterpreted as the signature of a different domain state. Secondly, the different published methods for determining the coercivity of remanent magnetisation are assessed and it is shown that the same sample can plot in a variety of different locations within the space of the Day plot depending on which method is employed.


magnetic hysteresis coercivity of remanence superparamagnetism 


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  1. Bertotti G., 1998. Hysteresis in Magnetism for Physicists, Material Scientist and Engineers., Academic, San Diego.Google Scholar
  2. Day R., Fuller M. and Schmidt V.A., 1977. Hysteresis properties of titanomagnetites: Grainsize and composition dependence. Phys. Earth Planet. Int., 13, 260–267.CrossRefGoogle Scholar
  3. Dunlop D., 2002. Theory and application of the Day plot (Mrs/Ms versus Hcr/Hc) 1. Theoretical curves and tests using titanomagnetite data. J. Geophys. Res., 107, 10.1029/2001JB000487.Google Scholar
  4. Dunlop D. and Özdemir Ö., 1997. Rock Magnetism: Fundermentals and frontiers, Cambridge University Press, Cambridge.Google Scholar
  5. Fabian K. and von Dobeneck T., 1997. Isothermal magnetisation of samples with stable Preisach function: A survey of hysteresis, remanence, and rock magnetic parameters. J. Geophys. Res., 102, 17659–17677.CrossRefGoogle Scholar
  6. García-Otero J., Porto M. and Rivas J., 2000. Henkel plots of single-domain ferromagnetic particles. J. Appl. Phys., 87, 7376–7381.CrossRefGoogle Scholar
  7. García-Otero J., Porto M., Rivas J. and Bunde A., 1999. Monte Carlo simulation of hysteresis loops of single-domain particles with cubic anisotropy and their temperature dependence. J. Magn. Magn. Mater., 203, 268–270.CrossRefGoogle Scholar
  8. Lanci L. and Kent D., 2003. Introduction of thermal activation in forward modeling of hysteresis loops for single-domain magnetic particles and implications for the interpretation of the Day diagram. J. Geophys. Res., 108, 2142, 10.1029/2001JB000944.CrossRefGoogle Scholar
  9. Metropolis N., Rosenbluth A.W., Rosenbluth M.N., Teller A.H. and Teller E., 1953. Equation of state calculations by fast computing machines. J. Chem. Phys., 21, 1087–1092.CrossRefGoogle Scholar
  10. Muxworthy A., Williams W. and Virdee D., 2003. The effect of magnetostatic interactions on the hysteresis parameters of single-domain and pseudo-single domain grains. J. Geophys. Res., 108, 2517, 10.1029/2003JB002588.Google Scholar
  11. Stoner E.C. and Wohlfarth E.P., 1948. A mechanism of magnetic hysteresis in heterogeneous alloys. Philos. Trans. R. Soc. Lond. Ser. A-Math. Phys. Eng. Sci., A240, 599–642.Google Scholar
  12. Tauxe L., Bertran H.N. and Seberino C., 2002. Physical interpretation of hysteresis loops: Micromagnetic modeling of fine particle magnetite. Geochem. Geophys. Geosyst., 3, 1–22.CrossRefGoogle Scholar
  13. Tauxe L., Mullender T.A.T. and Pick T., 1996. Potbellies, wasp-waists and superparamagnetism in magnetic hysteresis. J. Geophys. Res., 101, 571–583.CrossRefGoogle Scholar
  14. Thompson R. and Oldfield F. 1986. Environmental Magnetism. Allen and Unwin, London.Google Scholar

Copyright information

© StudiaGeo s.r.o. 2005

Authors and Affiliations

  • D. Heslop
    • 1
  1. 1.Universität Bremen, FB GeowissenschaftenBremenGermany

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