Magnetic and Mössbauer studies of Sn substituted rare earth iron garnets

Abstract

We report here magnetic and 57Fe Mössbauer studies on the substituted garnet system, {R 3− x Ca x }[Sn x Fe 2− x ](Fe 3)O 12. Measurements of the Curie temperature ( T c) on these samples indica that T c falls rapidly with increasing x. This is explained in terms of reduced a– d exchange interaction based on Gilleo's statistical model for YIG. Mössbauer spectra show expected hyperfine structure. An unusual feature in this system is that, for X = 1.0 composition, even though T c is ≈ 280 K, the Mössbauer spectra show broad and unresolved structures at 80 K which may be due to relaxation effects of cluster formation.