Showing results 21 to 23 of 23
   Roughness evolution of some X-UV reflective materials induced by low energy (< 1 keV) ion beam millingGailly, Patrick  ; Jamar, Claude ; Fleury-Frenette, Karl et alin Nuclear Instruments & Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (2004), 216 Ion beam figuring (IBF) is an advanced technique that is been used for more than 10 years as a final step in the manufacturing of optical elements. It makes use of ion sputtering to correct shape defects ... [more ▼] Ion beam figuring (IBF) is an advanced technique that is been used for more than 10 years as a final step in the manufacturing of optical elements. It makes use of ion sputtering to correct shape defects but this process may eventually lead to the degradation of the surface roughness. In this study, the evolution of roughness for some optical materials subjected to the ion beam figuring process has been investigated by using optical profilometry and scanning electron microscopy. Emphasis has been made on electroplated nickel, PVD gold and CVD silicon carbide. These materials are often used for X-ray and UV applications but only limited data on their behavior under ion milling is currently available. Roughness measurements have been performed at different etching depths down to 5 mum which is representative of typical IBF treatments. The effects of using different inert gases (Ar, Kr and Xe) with ion energies ranging from 200 to 900 eV have been studied. The observed trends are an important increase of the roughness for electroplated nickel, a slight decrease for PVD gold and a slight increase for CVD silicon carbide. Results are discussed in relation to previous related works and within sputtering considerations. (C) 2003 Elsevier B.V. All rights reserved. [less ▲] Detailed reference viewed: 16 (3 ULg)A magnetic and conversion electron Mossbauer spectral study of amorphous Dy20Fe80-yCoy thin filmsFleury-Frenette, Karl ; Delwiche, Jacques ; Grandjean, Fernande et alin IEEE Transactions on Magnetics (2001), 37(4), 2311-2314 Amorphous thin films of Dy20Fe80-yCoy, with 0 < y < 20 and of ca. 40 nm thickness, have been prepared by sputtering on polyimide substrates. The 295 K conversion electron Mossbauer spectra (CEMS) of these ... [more ▼] Amorphous thin films of Dy20Fe80-yCoy, with 0 < y < 20 and of ca. 40 nm thickness, have been prepared by sputtering on polyimide substrates. The 295 K conversion electron Mossbauer spectra (CEMS) of these films consist of broadened sextets which have been analyzed with a distribution of hyperfine fields in which the iron moments are oriented perpendicular to the plane of the film, an orientation which is in agreement with the perpendicular magnetic anisotropy observed herein at 295 K by vibrating sample magnetrometry. The average hyperfine field and isomer shift increase linearly with increasing Co content. Both increases arise from an increase in the electron occupation of the 3d states as the cobalt content increases. [less ▲] Detailed reference viewed: 11 (5 ULg)Characteristics of the iron moment in Dy-Fe and Dy-FeCo amorphous alloys studied by X-ray magnetic circular dichroismFleury-Frenette, Karl ; ; et alin Journal of Magnetism & Magnetic Materials (2000), 220(1), 45-51 The local magnetic moment of Fe in Dy-Fe and Dy-FeCo amorphous alloys has been studied using X-ray absorption spectroscopy and X-ray magnetic circular dichroism (XMCD). The Fe orbital and spin magnetic ... [more ▼] The local magnetic moment of Fe in Dy-Fe and Dy-FeCo amorphous alloys has been studied using X-ray absorption spectroscopy and X-ray magnetic circular dichroism (XMCD). The Fe orbital and spin magnetic moments have been obtained for a range of alloy compositions by applying the sum rules to the XMCD spectra. The room temperature variations of the average components of the Fe moments as a function of Dy concentration and with the substitution of Fe by Co have been determined. A sharp reversal of the total magnetic moment was found at 28 +/- 1 at% Dy for both alloys. (C) 2000 Elsevier Science B.V. All rights reserved. [less ▲] Detailed reference viewed: 24 (4 ULg)
|
||
