Influence of extreme dilutions on the magnetic properties of single-domain particle aggregates

Various magnetic properties of samples of single-domain particles dispersed in a nonmagnetic matrix are examined as functions of the packing fraction
p
. The range of variability of
p
is from 0.0003 to 0.20. The squareness ratio and the rotational and alternating hysteresis integrals change with
p
, while the coercive field, the initial anhysteretic susceptibility, and the areas between the remanence curves are not dependent on
p
. These results are interpretated as a consequence of the formation of agglomerates interacting with each other, rather than as a consequence of analogous interactions among the single-domain particles which are in the aggregate.