Reference : Magnetic and conversion electron Mössbauer spectral study of amorphous thin films of ...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Physics
http://hdl.handle.net/2268/198996
Magnetic and conversion electron Mössbauer spectral study of amorphous thin films of DyxFe100-x and Dy20Fe80-yCoy
English
Fleury-Frenette, Karl mailto [Université de Liège - ULiège > > CSL (Centre Spatial de Liège) >]
Delwiche, Jacques mailto [Université de Liège - ULiège > Services généraux (Faculté des sciences) > Relations académiques et scientifiques (Sciences) >]
Grandjean, Fernande mailto [Université de Liège - ULiège > Département de physique > Département de physique >]
Vandormael, D. [Institute of Physics, B5, University of Liège, B-4000 Sart-Tilman, Belgium]
Long, G. J. [Department of Chemistry, University of Missouri-Rolla, Rolla, MO 65409-0010, United States]
2001
Journal of Applied Physics
90
4
1934-1940
Yes (verified by ORBi)
International
0021-8979
1089-7550
[en] magneto-optical ; thin films ; dysprosium
[en] Amorphous thin films of DyxFe100-x and Dy20Fe80-yCoy, with various x and y values and of ∼40 nm thickness, have been prepared by sputtering on polyimide films. Their magnetization curves and the Mössbauer spectra indicate that at 295 K the iron moments are preferentially oriented parallel to the film in Dy2Fe98 and that Dy6Fe94 is paramagnetic. The DyxFe100-x thin films, where x is 17, 20, 24, 29, 32, 35, and 37, show perpendicular magnetic anisotropies and moderate coercive fields of at most 150 kA/m, whereas the Dy20Fe80-yCoy thin films, where y is 8, 13, 16, and 20, thin films show stronger perpendicular anisotropies and larger coercive fields of ∼400 kA/m. The introduction of cobalt into the amorphous thin films increases their coercive field and the perpendicular magnetic anisotropy. The Mössbauer spectra of the DyxFe100-x and Dy20Fe80-yCoy amorphous thin films consist of broadened sextets which have been analyzed with a distribution of hyperfine fields by assuming that the iron moments are oriented perpendicular to the plane of the film. Detailed fits of the Mössbauer spectrum of Dy20Fe80 indicate that the cone angle of the iron magnetic moments cannot be determined with accuracy. The average hyperfine fields in the DyxFe100-x amorphous thin films are smaller than those in the crystalline dysprosium-iron intermetallic compounds. The average hyperfine field increases from ∼140 kOe in the DyxFe100-x films to ∼220 kOe in the Dy20Fe80-yCoy films, an increase which is in agreement with the increase in the saturation magnetization. The x dependence of the isomer shift indicates that there is strong dysprosium-iron bonding, whereas the y dependence of the isomer shift reveals an enhancement of the d-electron localization. From earlier x-ray magnetic circular dichroism results and the Mössbauer spectral results presented herein, iron magnetic moments of 0.87 or 0.67 μB, corresponding to 2.9 or 2.8 holes in the iron 3d band, have been obtained for the DyxFe100-x amorphous thin films with x greater or smaller than 27, respectively
Researchers ; Professionals
http://hdl.handle.net/2268/198996
10.1063/1.1385574

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