Tailoring of the properties of ferrites by latent track production

Over the past 20 years, researchers have endeavored to tailor the magnetic and magneto-optical properties of ferrites by ion irradiations in view of high-density data recording. High-energy heavy ion irradiations of such magnetic insulators provide a unique way to generate reproducible random composites of ferrimagnetic crystal and paramagnetic amorphous latent tracks. This paper briefly reviews the methods of characterization of such extended defects and the modifications of the physical properties of yttrium iron garnet (Y3Fe5O12), baryum hexaferrite (BaFe12O19) and magnetite (Fe3O4), induced by latent track production. The effects of the track-induced stresses on the magnetic anisotropy are discussed. The relevance of the use of effective medium approximations or mean field theories for modeling the magnetic permeability and optical absorption coefficient of such composites are also addressed.