Lead substitution in yttrium iron garnet

Polycrystalline and single crystal thin films of lead substituted Y3Fe5O12 (Pb-YIG) have been prepared. The lattice parameter (ao) has been measured as a function of composition and the relationship Δao = 0.040x Å and 0.060x Å for polycrystalline and epitaxially grown films, respectively has been deduced (x is the number of lead atoms per formula unit). From the behaviour of polycrystalline Pb-YIG upon annealing we conclude that the thin films have a non-equilibrium composition. The hyperfine fields at the 57Fe nuclei measured by the Mössbauer effect are essentially the same as those of YIG. The Mössbauer spectra of the epitaxially grown films demonstrate that a growth-induced uniaxial magnetic anisotropy is present.