Magnetic Properties of the Low-Temperature Form of Magnetite

Some of the magnetic properties of the orthorhombic form of magnetite $({\mathrm{Fe}}_3{\mathrm{O}}_4)$ have been studied from 2°K to the transition temperature (∼119°K). Both ferromagnetic resonance measurements on single crystals and coercive force measurements on small particles have been made. The “twinning” of orthorhombic magnetite has been investigated. The crystalline anisotropy constants have been determined; they are of the order of ${10}^6\hspace{0.17em}\mathrm{ergs}/{\mathrm{cm}}^3$ . The coercive force of single-domain and multidomain particles has been interpreted in terms of the crystalline anisotropy.