A conversion electron Mossbauer spectral study of Dy3Fe5O12 thin films

Thin films of the garnet, Dy3Fe5O12, have been sputtered on quartz plates u sing both a ceramic target of powdered Dy3Fe5O12 and a metallic target of D y and Fe. In the latter case, the metallic DyFe thin film has subsequently been oxidized at temperatures between 1173 and 1373 K. The x-ray diffractio n patterns and conversion electron Mossbauer spectra, CEMS, of the thin fil ms prepared from the ceramic target show only the garnet phase, whereas tho se of the thin films prepared from the metallic target show the garnet phas e and two impurity phases, Fe2O3 and DyFeO3. The CEMS of the ceramic target thin films indicate that the iron magnetic moments are not oriented along the [111] axis, as is usually observed in bulk materials, but are compatibl e with moments oriented along the [211] axis. Further, the relative areas o f the six lines of the five component sextets used to model the spectra rev eal that the hyperfine fields are rotated by 34 degrees from the normal to the thin films. In contrast, the relative areas of the Dy3Fe5O12 spectrum i n the metallic target films reveal that the hyperfine fields are rotated by 60 degrees from the normal to the thin films. Hence, the orientation of th e iron moments is influenced by the film preparation route.