  In inhomogeneous bulk ferromagnets, the dominating sources of spin disorder
are related to spatial variations of (i) the magnitude of the local saturation
magnetization and of (ii) the magnitude and/or direction of the magnetic
anisotropy field. For the particular example of a porous ferromagnet, where the
magnetization inhomogeneity is at maximum, we demonstrate, by means of
experimental neutron scattering data and micromagnetic simulations, the
anisotropic character of magnetization fluctuations induced by the dipolar
interaction.
