Ferrimagnetic Resonance Linewidth in Dense Polycrystalline Ferrites

The linewidth of polycrystalline ferrites has been calculated from the dipole narrowing theory including both anisotropy and porosity effects. It is shown that porosity broadening is successfully accounted for and that porosity is the dominant line broadener even in very dense ferrites. The temperature dependence of the linewidth for samples of yttrium iron garnet and manganese ferrite are in good agreement with the predictions of the theory. © 1963 The American Institute of Physics.