The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
S Armyanov - One of the best experts on this subject based on the ideXlab platform.
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crystallographic structure and magnetic properties of electrodeposited Cobalt and Cobalt Alloys
Electrochimica Acta, 2000Co-Authors: S ArmyanovAbstract:The connection between plating conditions and elements of the structure (phase composition, texture and its perfection, grain size) is considered first and then is discussed the correlation between structure parameters and magnetic properties. The structure parameters’ influence on magnetic properties is explained in light of the contribution of different types of magnetic energy. The dependence of magnetic properties of Cobalt layers on the phase composition and texture perfection is demonstrated using specific X-ray methods for their quantitative determination for the case of axial texture presence. The hierarchy of the structural parameters’ effect on the magnetic properties of electrodeposited Cobalt is outlined. The influence of internal stress (caused by hydrogen desorption) on the magnetic properties of electrodeposited Cobalt is illustrated in case, where the structure remains unchanged. The data for the calculated (on the base of the existing axial texture) and the measured values of magnetostriction of Co‐Fe coatings are compared. The dependence of coercivity on Co‐Ni alloy composition is explained by assuming simultaneous action of several structure parameters. A possible influence of interparticle separation along the grain boundaries on the magnetic properties of electrodeposited films is briefly considered. © 2000 Elsevier Science Ltd. All rights reserved.
H. R. Kirchmayr - One of the best experts on this subject based on the ideXlab platform.
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Permanent magnets and hard magnetic materials
Journal of Physics D: Applied Physics, 1996Co-Authors: H. R. KirchmayrAbstract:This review deals with the definition and development of hard magnetic materials with special emphasis on more recent developments in this field. After discussing the fundamental properties of all hard magnetic materials, based on the intrinsic and extrinsic properties, some remarks on the history of hard magnetic materials and permanent magnets are given. The important hard ferrites are only briefly treated. Emphasis, however, is laid on the rare earth (RE) intermetallics and the hard magnetic materials based on them. Experimental techniques for the measurement of the basic properties of hard magnetic materials, e.g. the ordering temperature, the magnetization, the anisotropy field, the physical and technical hysteresis loop and the properties, derived from this loop are discussed. Examples of modern permanent magnets, based on RE - Cobalt Alloys, on RE - Fe - B Alloys and RE - Fe - nitrides, etc are explained. The principles of the production of sintered and bonded magnets are given. Finally some typical applications of these modern permanent magnets are discussed with respect to the different properties of the materials. Future developments and the possibility of superconducting permanent magnets are briefly discussed. Concluding remarks are concerned with the possibilty and necessity of still larger energy products at elevated temperatures and the benefits of high-tech permanent magnets for modern and energy saving devices.
J M Sanchez - One of the best experts on this subject based on the ideXlab platform.
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structure and magnetism in bcc based iron Cobalt Alloys
Physical Review B, 2006Co-Authors: Alejandro Diazortiz, Ralf Drautz, M Fahnle, H Dosch, J M SanchezAbstract:The ordering and magnetic properties of bcc-based iron-Cobalt Alloys have been investigated as a function of the atomic composition. The different states of ordering in $\mathrm{Fe}\text{\ensuremath{-}}\mathrm{Co}$ Alloys, from the fully ordered to the disordered state, and their effect on the atomic volume, the magnetic moment, and enthalpy of formation, were described using the recently developed variational cluster expansion method based on first-principles data. The coarse-grained description of the energetics of the system allowed one to identify several new ordered structures, additional to the known $\mathrm{FeCo}\text{\ensuremath{-}}\mathrm{B}2$ (CsCl) ground state, after an extensive combinatorial search in the configurational phase space. It is found that the atomic volume and magnetic moment do not follow Vergard's law for either the ordered or disordered $\mathrm{Fe}\text{\ensuremath{-}}\mathrm{Co}$ Alloys. However, the equilibrium values of the atomic volume and the magnetic moment depend linearly on each other. The implications of such results on $\mathrm{Fe}\text{\ensuremath{-}}\mathrm{Co}$ nanostructured systems are discussed.
H Dosch - One of the best experts on this subject based on the ideXlab platform.
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structure and magnetism in bcc based iron Cobalt Alloys
Physical Review B, 2006Co-Authors: Alejandro Diazortiz, Ralf Drautz, M Fahnle, H Dosch, J M SanchezAbstract:The ordering and magnetic properties of bcc-based iron-Cobalt Alloys have been investigated as a function of the atomic composition. The different states of ordering in $\mathrm{Fe}\text{\ensuremath{-}}\mathrm{Co}$ Alloys, from the fully ordered to the disordered state, and their effect on the atomic volume, the magnetic moment, and enthalpy of formation, were described using the recently developed variational cluster expansion method based on first-principles data. The coarse-grained description of the energetics of the system allowed one to identify several new ordered structures, additional to the known $\mathrm{FeCo}\text{\ensuremath{-}}\mathrm{B}2$ (CsCl) ground state, after an extensive combinatorial search in the configurational phase space. It is found that the atomic volume and magnetic moment do not follow Vergard's law for either the ordered or disordered $\mathrm{Fe}\text{\ensuremath{-}}\mathrm{Co}$ Alloys. However, the equilibrium values of the atomic volume and the magnetic moment depend linearly on each other. The implications of such results on $\mathrm{Fe}\text{\ensuremath{-}}\mathrm{Co}$ nanostructured systems are discussed.
Takahiro Ogawa - One of the best experts on this subject based on the ideXlab platform.
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the effect of uv photofunctionalization on the time related bioactivity of titanium and chromium Cobalt Alloys
Biomaterials, 2009Co-Authors: Norio Hori, Fuminori Iwasa, Masahiro Yamada, Takeshi Ueno, Takahiro OgawaAbstract:Abstract This study examined the possible changes in the bioactivity of titanium surfaces during their aging and investigated the effect of ultraviolet (UV) light treatment during the age-related change of titanium bioactivity. Rat bone marrow-derived osteoblastic cells were cultured on new titanium disks (immediately after either acid-etching, machining, or sandblasting), 4-week-old disks (stored after processing for 4 weeks in dark ambient conditions), and 4-week-old disks treated with UVA (peak wavelength of 365 nm) or UVC (peak wavelength of 250 nm). During incubation for 24 h, only 50% of the cells were attached to the 4-week-old surfaces as compared to the new surface. UVC treatment of the aged surface increased its cell attachment capacity to a level 50% higher than the new surfaces, whereas UVA treatment had no effect. Proliferation, alkaline phosphatase activity, and mineralization of cells were substantially lower on the 4-week-old surfaces than on the new surfaces, while they were higher on the UVC-treated 4-week-old surfaces as compared to the new surfaces. The age-related impaired bioactivity was found on all titanium topographies as well as on a chromium–Cobalt alloy, and was associated with an increased percentage of surface carbon. Although both UVA and UVC treatment converted the 4-week-old titanium surfaces from hydrophobic to superhydrophilic, only UVC treatment effectively reduced the surface carbon to a level equivalent to the new surface. Thus, this study uncovered a time-dependent biological degradation of titanium and chromium–Cobalt alloy, and its restoration enabled by UVC phototreatment, which surmounts the innate bioactivity of new surfaces, which is more closely linked to hydrocarbon removal than the induced superhydrophilicity.