Superparamagnetic resonance of ferric ions in devitrified borate glass

摘要: Abstract Drastic changes are observed in magnetic resonance spectra of borate glasses doped with low concentrations iron oxide, after heat treatment above the glass transition temperature. A sharp g ef = 4.3 line, characteristic diluted Fe 3+ ions vitreous matrix, progressively disappears course treatment. new two-line pattern grows vicinity ≈ 2.0, consisting two superimposed features: a narrow one and broad one. The feature is dominant at lower temperatures, while broader rapidly higher temperatures. Computer simulations succeed fitting as being due to superparamagnetic static monodomain particles, randomly distributed matrix characterised by magnetocrystalline anisotropy constant, demagnetisation field line shape function depending on particle volume. shown result from unimodal log-normal distribution diameters, most probable diameter value increasing Such results very inhomogeneous matrix.