Growth-induced magnetic and optic anisotropy in bismuth-substituted iron garnet films

Abstract

The growth-induced uniaxial magnetic anisotropy constant Kgu and the growth-induced birefringence Δng of (111) oriented epitaxial iron garnet films of composition R3−xBixFe5−yAlyO12 with R=Y, Gd, Sm have been investigated as a function of supercooling temperature ΔTs. The uniaxial anisotropy constant Kgu increases linearly with increasing ΔTs (0≤ΔTs≤100 K) in agreement with results reported for other bismuth-substituted rare-earth iron garnets. Δng turns out to be a linear function of Kgu and ΔTs. Δng is independent of the rare-earth species R in contrast to Kgu. The optical anisotropy arises primarily from the iron ions on the octahedral and tetrahedral sites as could be shown by the strong influence of diamagnetic dilution of the iron sublattices in the garnet crystal.