Electronic Resource
Oxford, UK
:
Blackwell Publishing Ltd
Geophysical journal international
118 (1994), S. 0
ISSN:
1365-246X
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Geosciences
Notes:
The angular variation of the median destructive field (MDF) of magnetite particles has been determined by subjecting anisotropic samples carrying an isothermal remanent magnetization (IRM) to static AF demagnetization, with the AF at an angle to the IRM. The alignment was produced by dispersing the magnetite particles in resin in the presence of a magnetic field thus making the sample anisotropic. After tumble demagnetization, an IRM in 80 mT was given to each sample along the alignment axis. 11 different particle sizes were used covering the range 0.7–82 μm. The results for all the samples are remarkably similar in that the MDF is smallest when the AF is applied parallel to the alignment axis and greatest when the AF is perpendicular to the axis. The results are also very similar to those found experimentally for single-domain ‘tape’ particles and indicate that the reversal mechanism even in the smallest particles is not by coherent reversal as in the Stoner-Wohlfarth model. The angular variation of the MDF for all the particle sizes is described quite well by a function derived by Aharoni for single-domain particles. The MDF at θ= 0 is found to be inversely proportional to the square root of the particle size.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-246X.1994.tb04682.x
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