HR: 14:30h
AN: GP33A-02    [Abstracts]
TI: The effect of grain surface roughness on magnetic remanence in PSD magnetites
AU: * Williams, W
EM: wyn.williams@ed.ac.uk
AF: School of GeoSciences, Univeristy of Edinburgh West Mains Road , Edinburgh, EH9 3JW, United Kingdom
AB: Numerical micromagnetic models have been very successful in being able to predict the variation in domain structure as a function of grains size and shape for magnetite particles above the critical single domain grains size d0. In fact recent results have shown that considerable variation in stability of magnetic remanence can result from variations in shape between cubic, octahedral and tetrahedron grains, resulting in single-domain like stabilities even for grains well above the critical SD grain size. Numerical micromagnetic models are now of sufficient resolution to allow examination of the effect of surface roughness, both of the domain structures that can be nucleated within a grain, and of their magnetic stability. This presentation will show the results from dynamical solutions of a finite-element micromagnetic model that examines the effect of surface roughness as a function of amplitude and frequency on pseudo-single-domain grains of magnetite. Simulated hysteresis show of the nucleation of domain switching and variation of coercivity can vary, with implications for the stability of palaeomagnetic remanences.
DE: 0560 Numerical solutions (4255)
DE: 1540 Rock and mineral magnetism
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Joint Assembly