Bibliothek

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • Digitale Medien  (15)
  • 1995-1999  (15)
Materialart
  • Digitale Medien  (15)
Erscheinungszeitraum
Jahr
  • 1
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 5816-5818 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Magnetization reversal modes and coercivities were calculated for a magnetic particle with thickness : width : length aspect ratios 0.1 : 1 : 5 as a function of the reduced particle width d/lex, where d is the particle width and lex is the intrinsic magnetostatic exchange length. With only exchange energy and magnetostatic energy included, the particle corresponds to μMAG standard problem No. 2. The problem is modeled with two-dimensional grids of three-dimensional spins, and the results are compared for two methods of calculating magnetostatic energies, the "constant magnetization" method and the "constant charge" method. For both magnetostatic computational methods, the coercivity decreases from Hc/Ms=0.06±0.003 to 0.014±0.003 over the range 3〈d/lex〈80, where the uncertainties reflect the field step size. Also over this interval, as d/lex increases, the magnetization exhibits three modes of reversal: nearly uniform rotation, transverse switching of end domains followed by propagation of head-to-head domain walls from the ends to the center of the particle, and nucleation and propagation of vortices accompanied by more complex domain structures. © 1999 American Institute of Physics.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 81 (1997), S. 5242-5242 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Proposed solutions to a standard problem in micromagentics that were collected anonymously from a number of researchers using a variety of computational techniques are presented. This is the first time that a problem in micromagnetics has been attempted by a group. The sample problem is a 1 μm×2 μm rectangular element of Permalloy film, 20 nm thick. The material properties are specified by an exchange stiffness constant, A=1.3×10−11 J/m, a magnetization, M=8.0×105 A/m, and a uniaxial ansotropy constant, K=5.0×102 J/m3 with the easy axis directed parallel to the long edge of the sample. The requested calculations are hysteresis loops for fields directed one degree away from the long and short axes and magnetization configuration data for the remanent states. The results collected show a surprising lack of agreement. For fields applied nearly parallel to the long axis of the sample problem, calculated coercivities range from 2.4 to 33 mT, squareness values range from 0.23 to 1.00, and there is a variety of hysteresis loop shapes and mazgnetization patterns. Similar differences exist in the results for fields applied nearly parallel to the short axis of the sample. Differences in computational methods that give rise to the disparity in the results, e.g., grid geometry and size and magnetostatic field calculation methods, are highlighted.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 5183-5191 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We have investigated the use of Pb and Au as surfactants in an attempt to achieve smoother and sharper interfaces in three types of giant magnetoresistance (GMR) spin valve multilayers: symmetric spin valves, bottom spin valves, and top spin valves. The coupling fields are reduced by a factor of 10 for symmetric and bottom spin valves and by a factor of 3 for top spin valves, presumably by suppressing roughness and interdiffusion at the Co/Cu/Co interfaces, when ∼1 monolayer of Pb is deposited in the early stages of spin valve growth. The Pb has a strong tendency to float out or segregate to the surface during deposition of the spin valve leaving the GMR largely unaltered. Au is almost as effective as Pb, however the Au tends to be left behind in the spin valve, and the GMR is reduced slightly. Attempts to use Hg as a surfactant were unsuccessful. The coupling field increased, and the GMR decreased sharply. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A magneto-optical indicator film (MOIF) technique and magnetic force microscopy were used for visualization and direct real-time experimental study of the magnetization processes of magnetic Co90Ag10 granular films. It is shown that the magnetization reversal of the as-deposited films follows a specific two-step course. The first stage is characterized by gradual spin rotation to large angles up to 90° without domain formation. Further magnetization reversal proceeds by the nucleation and motion of zigzag-shaped domain walls. The dendritic structure of the domain walls was observed using both techniques. Also tracks of magnetic inhomogeneities remaining behind moving zigzag-shaped domain walls was revealed by MOIF. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 5456-5458 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Magnetic properties of three kinds of nanograin Fe powder were studied. The first two, designated as NM(Ar) and NM(N), were obtained by ball milling the iron powder under an argon or nitrogen atmosphere. The third, designated NN, was obtained by evaporation and condensation. They have grain sizes of 20, 7, and 60 nm, respectively. The particle sizes of the first two were in the micrometer range, whereas those of the NN were in the nanometer range. The NN powder exhibited a coercivity of 79 mT; its magnetic moment at saturation was lower than that of bulk iron. The coercivities of the NM(N) and NM(Ar) were much smaller and their magnetic moment values at high fields were closer to that of bulk iron (210 A⋅m2/kg). The NM(N) and NN samples exhibited marked time dependences of the magnetic moments following a relatively abrupt change of the applied field. The moment changes by more than 0.5% of the saturation moment within 50 min and continues to change for many hours. Much smaller effects were detected in the NM(Ar) sample. The viscosities were investigated as a function of temperature and jump field. The results showed differences in the behavior of the three samples. The powders were consolidated by cold isostatic pressing followed by sintering at around 600 °C for several hours. The magnetic behavior of the sintered samples approach that of bulk iron. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 6
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We have investigated the use of various alloys as substitutes for pure Co in the center film of symmetric spin valves of the type NiO/Co/Cu/Co/Cu/Co/NiO. The aim of this work is to identify magnetic materials that exhibit smaller coercivities than pure Co for the center or "valve'' film but which retain much of the giant magnetoresistance associated with a pure Co film. The materials investigated include Co95Fe5, Co90Fe10, Ni80Fe20, Co86Fe10.5Ni3.5, and Co85B15. It appears that each of these alloys scatters electrons more strongly than does pure Co as they cross the center film. This scattering degrades the dual spin-valve effect, which is the primary advantage of the symmetric spin valve. As a result, a tradeoff exists between large GMR and small coercivity when using these materials. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 7
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We have attempted to optimize the values of the giant magnetoresistance in symmetric spin valves of the type NiO/Co/Cu/Co/Cu/Co/NiO (achieving 23.4%) and in bottom spin valves of the type Co/Cu/Co/NiO (achieving 17.0%), the largest values ever reported for such structures. The key elements in this achievement are improved vacuum conditions and careful attention to the film thicknesses. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We report on the possibilities of application of magneto-optical indicator film (MOIF) technique for visualization and direct experimental study in real time of the magnetization processes and nondestructive characterization of the quality of magnetic thin granular films and multilayers. The technique utilizes a transparent indicator film, a Bi-substituted iron garnet with in-plane anisotropy, placed on the top of a sample. Polarized light passes through the indicator film and is reflected back by an Al underlayer. Magnetic stray fields with a component perpendicular to the film plane are observed through the magneto-optic Faraday effect created in the garnet film. An investigation of the magnetic moment distribution in granular single films and multilayers was carried out using this method. Some examples of magnetic stray field images of domain walls of different types obtained by MOIF technique and magnetic force microscopy are described. The experimental data are compared with theoretical estimations. The detailed information is obtained on the spin rotation processes as well as on the domain wall nucleation and motion during the remagnetization of these materials. Peculiarities of the magnetization reversal of multilayers with different types of exchange interlayer coupling have been revealed and discussed. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 9
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 5998-6000 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We have investigated the sensitivity of structural, magnetic, and magnetocaloric properties of (Hf0.83Ta0.17)Fe2+x alloys (x=−0.18, −0.09, −0.02, 0.00, 0.09, 0.26) to Fe content. As-cast samples for all x consist essentially exclusively of hexagonal MgZn2-type material. Via magnetization and differential scanning calorimetry measurements we find that all the alloys except x=0.26 feature both a ferromagnetic→antiferromagnetic (FM→AFM) transition at temperature T0 and a Néel transition. The most abrupt FM→AFM transition occurs in the x=−0.02 material which also exhibits the lowest T0 and largest low-temperature moment. We report a magnetocaloric property, the field-induced entropy change ΔS, for the x=0.00 and x=±0.09 alloys. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 10
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 2491-2496 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We have investigated the use of In as a surfactant to achieve smoother interfaces in spin-valve multilayers of the general type: FeMn/Ni80Fe20/Co/Cu/Co/Ni80Fe20/glass. The coupling field is reduced from ∼0.8 to ∼0.3 mT, presumably by suppressing roughness at the Co/Cu/Co interfaces, when 0.5–1.0 nm In is deposited on the first Co film just prior to Cu deposition or on the Cu film just prior to deposition of the second Co film. The In has a strong tendency to float-out to the surface during deposition of the spin valve leaving the spin-valve layers largely intact. The exchange bias at the FeMn/Ni80Fe20 interface can be increased from 12 to 25 mT by the use of thicker In (1.4 nm). © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...