Ferromagnetic Resonance in Si-Doped YIG

Abstract

The magnetocrystalline anisotropy of Fe2+ ions in YIG has been studied by means of FMR at 10 and 30 GHz at temperatures between 4° and 400°K. Below 50°K strong magnetic anneal occurs. Anneal fields were in the [100], [111], and [110] directions. The g factor is 1.98 at 4.2°K and 1.96 at 290°K. At low temperature the resonance field HR is less than ω/γ by as much as 2000 Oe for all orientations in the (110) plane. The HR versus angle curves are explained quantitatively by taking into account canting of the spins around the Fe2+ ions as well as perturbing electrostatic fields of the neighboring Si ions. The correct temperature dependence and anisotropy of the linewidth ΔH also follow from the model calculation.