A conversion electron mossbauer spectral study of Dy{sub}3Fe{sub}5O{sub}12 thin films

摘要

Thin films of the garnet, Dy{sub}3Fe{sub}5O{sub}12, have been sputtered on quartz plates using both a ceramic target of powdered Dy{sub}3Fe{sub}5O{sub}12 and a metallic target of Dy 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 diffraction patterns and conversion electron Mossbauer spectra, CEMS, of the thin films prepared from the ceramic target show only the garnet phase, whereas those of the thin films prepared from the metallic target show the garnet phase and two impurity phases, Fe{sub}2O{sub}3 and DyFeO{sub}3. 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 compatible with moments oriented along the 211 axis. Further, the relative areas of the six lines of the five component sextets used to model the spectra reveal that the hyperfine fields are rotated by 34° from the normal to the thin films. In contrast, the relative areas of the Dy{sub}3Fe{sub}5O{sub}12 spectrum in the metallic target films reveal that the hyperfine fields are rotated by 60° from the normal to the thin films. Hence, the orientation of the iron moments is influenced by the film preparation route.