A magnetic and conversion electron Mossbauer spectral study of amorphous Dy20Fe80-yCoy thin films

Amorphous thin films of Dy20Fe80-yCoy, with 0 < y < 20 and of ca. 40 nm thi ckness, have been prepared by sputtering on polyimide substrates. The 295 K conversion electron Mossbauer spectra (CEMS) of these films consist of bro adened sextets which have been analyzed with a distribution of hyperfine fi elds in which the iron moments are oriented perpendicular to the plane of t he film, an orientation which is in agreement with the perpendicular magnet ic anisotropy observed herein at 295 K by vibrating sample magnetrometry. T he average hyperfine field and isomer shift increase linearly with increasi ng Co content. Both increases arise from an increase in the electron occupa tion of the 3d states as the cobalt content increases.