Domain-Wall Motion in Yttrium-Iron Garnets

Abstract

Domain‐wall motion in pure and doped yttrium‐iron‐garnet single crystals with composition Y₃Fe_5−δSi_δO₁₂, 0<δ2+ ion concentration). However, as a function of temperature the inverse mobility of silicon‐doped samples, unexpectedly, shows a peak at about 20°K. The over‐all temperature dependence does not agree with the diffusion after‐effect model which is based on the assumption that wall damping is the result of 3d‐electron transitions between Fe²⁺ and Fe³⁺ cations in the octahedral sublattice. The behavior, however, is very similar to that found for the temperature dependence of the microwave‐resonance linewidth of silicon‐doped samples. In both cases, because of the short time of spin reorientation relative to the electron‐diffusion relaxation time, it is more likely that the loss mechanism is dominated by a localized relaxation process occurring between the energy levels of Fe²⁺ ions.