A study has been made of the magnetic properties of ferromagnetic powder suspended in a nonmagnetic matrix. The study was motivated by a desire to predict the properties of keepers employed in some fast computer memories. Expressions are obtained which give the static susceptibility and useful frequency range of such materials. The susceptibility is found to be small and relatively independent of that of the parent material. However, the useful frequency range is greatly increased. The analysis is used to evaluate effective demagnetizing factors and interaction fields in quasiuniformly magnetized bodies. It is shown that the theory is consistent with certain experimental findings concerning polycrystalline ferrites and YIG. Finally, a suggestion is made for possible observation of domain-wall resonance. © 1968 The American Institute of Physics.
