Transverse susceptibility and anisotropy fields of iron-oxide pigments

The transverse susceptibility of oriented iron oxide samples was measured. The results are in qualitative agreement with theoretical curves. From singular points of the transverse susceptibility the anisotropy fields of the pigments were determined. For Co-free pigments these agree well with the chain of spheres model. The anisotropy fields of the Co-modified pigments depend significantly on the kind of modification. This is interpreted with differences in the strength of uniaxiality of the anisotropy.<
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