HR: 1340h
AN: GP23A-0175    [Abstracts]
TI: Magnetostatic interaction fields in First-order-reversal-curve (FORC) diagrams.
AU: Williams, W
EM: Wyn.Williams@ed.ac.uk
AF: School of Geoscience, University of Edinburgh, Edinburgh, EH9 3JW United Kingdom
AU: * Muxworthy, A R
EM: Adrian.Muxworthy@ed.ac.uk
AF: School of Geoscience, University of Edinburgh, Edinburgh, EH9 3JW United Kingdom
AB: From experiments it is known that magnetostatic interactions between grains strongly affect the magnetic hysteresis behaviour of samples, however, because of the difficulty in predicting the non-linear behaviour our knowledge of the contribution of interactions to hysteresis and in particular first-order-reversal-curve (FORC) diagrams is limited. Previous FORC simulations of three-dimensional structures have been considered only the effect of interactions on the FORC diagram itself. To better understand the relationship between FORC diagrams and interactions, in this new study we examine the shape of the interaction field distribution (IFD) and how it changes during a FORC simulation for assemblages of ideal single domain (SD) grains. The IFDs tend to be more Gaussian on average than Cauchian as predicted analytically for disordered systems, due to ordering during FORC diagram determination. The spreading of the FORC distribution in the vertical direction of the FORC diagram, is shown to be directly related to the mean standard deviation of the IFD during the FORC measurement, with a small offset related to the smoothing factor. We use for the first time in our FORC simulations a three-dimensional dynamic micromagnetic algorithm that solves for the Landau-Liftshitz-Gilbert equation.
DE: 3210 Modeling
DE: 3230 Numerical solutions
DE: 1512 Environmental magnetism
DE: 1540 Rock and mineral magnetism
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2004 AGU Fall Meeting