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Amorphous thin films of DyFe and DyFeCoy, with various x and y values and of ~40 nm thickness, have been prepared by sputtering on polyimide films. Their magnetization curves and the Mssbauer spectra indicate that at 295 K the iron moments are preferentially oriented parallel to the film in DyFe and that DyFe is paramagnetic. The DyFe 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 DyFesCo thin films, wherey 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 Mssbauer spectra of the DyFe and DyFeCo 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 Mssbauer spectrum of DyFe indicate that the cone angle of the iron magnetic moments cannot be determined with accuracy. The average hyperfine fields in the DyFe amorphous thin films are smaller than those in the crystalline dysprosium--iron intermetallic compounds. The average hyperfine field increases from ~140 kOe in the DyFe films to ~220 kOe in the DyFeCo 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 Mssbauer spectral resu... [ABSTRACT FROM AUTHOR]

Surface plasmons resonance (SPR) architectures based on grating coupler/disperser combination is an attractive alternative for spectral-based biochemical sensing. In this paper, we investigate theoretically and experimentally a new concept where the plasmon coupling occurs through a thin film grating and sensing occurs via the first evanescent diffraction order in transmitive mode. The surface plasmon wave excitation induces a peak in the wavelength as well as in the angular spectra of the detected first transmitted diffraction order. Accordingly, a change in SPR spectrum of the detected diffraction order can be used to quantify the amount of the target molecules immobilized on the sensor surface, and therefore, the concentration of these molecules in the analyte solution. The developed sensor architecture is dedicated to droplet biochemical sensing and appears to be especially suitable for biosensor integration and miniaturization. The presented sensor concept is perfectly suited for mass production of low-cost and reproducible SPR sensor chip for biochemical analysis. The implemented setup gives access to multichannel biosensing with the potential for efficient internal referencing essential to achieve sufficiently high reproducibility and accuracy of the measurements. [ABSTRACT FROM AUTHOR]

Provides information on a study that examined amorphous thin films of Dy...Fe...Co... prepared by sputtering on polymide substrates. Methodology of the study; Results and discussion on the study; Conclusion.

The surface roughness evolution of two silica-based sol–gel materials under 650 eV argon ion beam sputtering has been investigated. The liquid sol–gel solutions were applied on silicon substrates using the dip coating technique and thermally cured to obtain thin solid films and their thicknesses were then controlled over the samples surface using spectroscopic ellipsometry. The surface roughness of the sol–gel films was measured using both interferometric profilometry and atomic force microscopy depending on the obtained sputtering depths. We observed a significant increase of the roughness according to the sputtering depth, faster in the case of sol–gel layers than with bulk fused silica. Interestingly, the sputtering rates of the sol–gel layers were found much higher than the rate obtained on bulk fused silica. The development of micron scale holes with relatively stable interstices is supposed to rule the surface roughness evolution. AFM measurements revealed a regular submicron scale lateral structure which nanometric amplitude is amplified within sputtering. [ABSTRACT FROM AUTHOR]