Physical properties of magnetic grains dispersed in anisotropic media

We calculate the dynamical response of a group of non-interacting magnetic grains dispersed in a medium that imposes on them an uniaxial anisotropy. Numerical results are obtained for a collection of grains that has its volume distribution given by a Gaussian function centered in the average volume V 0, and has a width σV 0. We assume that the only effect of the medium on the particles is the anisotropy imposed on the grains to study the influence of the volume distribution (σ and V 0) on the effective permeability. The results are analyzed through the calculation of numerical values for the components of the magnetic permeability and also by the analysis of the combined effect of the external dc magnetic field and the width of the volume distribution on the skin depth. Copyright EDP Sciences/Società Italiana di Fisica/Springer-Verlag 200675.40.Gb Dynamic properties (dynamical susceptibility, static susceptibility, spin waves, spin diffusion, dynamic scaling, etc.), 75.50.Kj Amorphous and nanocrystalline magnetic materials; quasicrystals, 75.50.Tt Fine-particle systems; nanocrystalline materials,