Coercivity and switching field of single domain γ-Fe2O3 particles under consideration of the demagnetizing field

The coherent rotation of the spontaneous polarization in ellipsoidal ferromagnetic single domain particles is calculated under consideration of the magnetocrystalline anisotropy and the true, inner field. Magnetization curves and switching fields are computed for uniaxial and cubic magnetocrystalline and shape anisotropy. Considering only the magnetic energy inside the particle, the resulting switching fields are lower than those predicted by the Stoner–Wohlfarth theory, and they are qualitatively and quantitatively comparable to the results of other models. The comparison to measurements on isolated γ-Fe2O3 particles shows excellent agreement.