1,720,992 research outputs found
Morphological, magnetic and microstructural study of Fe/Co multilayers grown at different temperatures
No full textIndustrial applications of Mössbauer Spectroscopy
No full textA review of the industrial applications of Mössbauer Spectroscopy is presented underlining the powerfulness and usefulness of the technique in the
control and optimization of the production processes. A few examples are reported concerning the developments of thin protective coatings for structural parts and media for the magnetic recording field
Magnetic anisotropy and exchange interactions in Fe/Co multilayers grown on different substrates
No full textEffects of the elemental layer thickness on the properties of Fe/Co grown at 200 °C.
No full textThin Fe/Co multilayers were grown at 200 °C onto glass and naturally oxidized Si substrates, changing the elemental layer thickness. Onto glass substrates, the multilayers show a large in-plane uniaxialmagnetocrystalline anisotropy, which strengthens by increasing the Fe layer thickness. Onto naturally oxidized Si substrates, an appreciable out-of-plane contribution to the magnetization vector is present. This can be due to the absence in the
multilayer stack of a pure-Co layer as a consequence of a large intermixing occurring at the Fe/Co interfaces, that gives rise to a structure only constituted by intercalated Fe and FeCo layers. However, by increasing the Co and Fe layer thickness, the intermixing lowers because of a change in the sample morphology and microstructure, which determines the disappearance of the out-of-plane tilting of the magnetization vector while promoting the establishing of an in-plane anisotropy
Colorimetric-Spectral Clustering: a tool for multispectral image compression
No full textIn this work a new compression method for multispectral images has been proposed: the ‘colorimetric–spectral clustering’. The basic idea arises from the well-known cluster analysis, a multivariate analysis which finds the natural links between objects grouping them into clusters. In the colorimetric–spectral clustering compression method, the objects are the spectral reflectance factors of the multispectral images that are grouped into clusters on the basis of their colour difference. In particular two spectra can belong to the same cluster only if their colour difference is lower than a threshold fixed before starting the compression procedure. The performance of the colorimetric–spectral clustering has been compared to the k-means cluster
analysis, in which the Euclidean distance between spectra is considered, to the principal component analysis and to the LabPQR method. The colorimetric–spectral clustering is able to preserve both the spectral and the colorimetric information of a multispectral image, allowing this information to be reproduced for all pixels of the image
Morphological and microstructural study of L10-ordered FePt and L10-FePt/Fe ultrathin films grown by UHV e-beam evaporation technique
No full textInfluence of the phenomena occurring at the soft/hard interface on the coercivity behavior in exchange-spring magnets
No full textL10-ordered FePd thin films were grown onto MgO-(100) monocrystalline substrates at 450 and 650 °C by means of a molecular beam epitaxy system. Fe/FePd bi-layers were grown by covering the L10-FePd hard films with Fe layers of different thickness. For a soft/hard thickness ratio up to 1, these bi-layers show behavior typical of a single phase hard magnet while, for a higher thickness ratio, they behave as exchange-coupled magnets characterized by two critical fields. The bi-layers’ coercivity decreases as a function of the deposited Fe when it is controlled by the domain wall pinning mechanism, while it initially increases and then decreases, when the nucleation of reversed domains is the predominant coercivity mechanism. These different behaviors are due to the phenomena occurring at the soft/hard interface and in particular to the degree of Fe/FePd intermixing and to the composition of the thin interfacial layer
Near-lossless compression methods for spectral images
No full textIn this work, several near-lossless compression methods for spectral images have been analyzed and compared. These methods are based both on the principal component analysis (PCA) and on the choice of a minimum number of spectral points, selected following different criteria. The analysis, initially carried out on 14 National Physical Laboratory tiles of certified colour, has been extended to some spectral images of paintings taken
at the National Gallery of Parma (Italy). The comparison of the results with those obtained by applying the PCA analysis shows that the best method indicated as ‘‘method of a few significant points’’ allows reducing the spectral image size of a factor of 10 without loss of spectral and colour information
Spontaneous exchange-bias in Fe/Mn thin multilayers
No full textFe/Mn multilayers were grown by means of a molecular beam epitaxy system onto quartz substrates changing the thickness of the elemental layers. A spontaneous unidirectional anisotropy develops for thickness of Fe or Mn layer of about 35 Å. Since the samples were no subjected to field cooling treatments during or after the growth, this kind of anisotropy can be explained considering besides the exchange coupling at the Fe/Mn interface, the structural disorder due to dislocations and defects. In effect, the appearance and strength of the exchange-bias field are depending on the surface roughness of the samples and are significantly enhanced by the formation of a structure constituted by islands showing a snake-like morphology. The fitting of the angular dependence of the exchange-bias field indicates that the associated anisotropy is due to the superposition of two contributions, the principal one with unidirectional symmetry and the other showing uniaxial characteristics
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