Abstract: The invention relates to the use of a powder composition comprising at least 95% by weight of magnetite (Fe3O4) particles as a magnetisable component in a medium for magnetically storing information. At least 99.9% by weight of the magnetite particles have a particle size of less than 5 ?m, and the magnetite particles have a polyhedral shape and essentially isotropic magnetic properties. The magnetite particles have a saturation magnetisation of 75-95 emu/g at 10 kOe, a remanence of 20-40 emu/g and a coercivity of 250-500 Oe. The invention also relates to the medium for magnetically storing information comprising magnetite particles.

Abstract: The invention concerns a new carrier core material having high voltage breakdown. The new material comprises a particulate ferrite base material having a substantially spherical particle shape, wherein the powder particles are coated with an inorganic, electrically insulating coating having a resistivity higher than that of the ferrite base material.

Abstract: The inventions concerns a new carrier core material consisting of particles of essentially pure, spherical magnetite. These particles are electrically insulated by an inorganic phosphorus containing coating.