ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
Collection
Years
  • 1
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 83 (1998), S. 2705-2714 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Magnetoresistive metal multilayers are known to undergo an irreversible decrease in the maximum value of their field-dependent resistance after exposure to a magnetic field. An explanation for this effect in terms of the creation of antiphase domain boundaries is considered and rejected on the basis of experimental tests that point instead to a strong correlation of irreversible loss of resistance with magnetoresistive hysteresis. The main features of the phenomenon are reproduced by a model that treats polycrystalline multilayers as assemblies of grains with random orientations of magnetic easy axes. The key feature of the model is that for each individual grain the magnetic state corresponds to an energy minimum that may be only local, rather than global. Trapping in local energy minima accounts for both magnetoresistive hysteresis and incomplete antiferromagnetic order at the maximum resistance that is attained after cycling. The model explains experimental observations, such as the relatively small hysteresis and resistance loss at the first antiferromagnetic maximum. It also predicts a strong Co-thickness dependence of the resistance loss in Co/Cu multilayers at the second antiferromagnetic maximum that is verified with experimental data for Co/Cu multilayers. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A description is given of the magnetoresistive properties of Co/Cu multilayers in which the thicknesses of antiferromagnetically coupled Co layers are alternated between two values. With such an arrangement, the thicker Co layers are coupled more strongly to applied magnetic fields than are the thinner Co layers. Consequently, one may attain conditions where the magnetization direction of the thinner Co layers is the result of a balance between the applied magnetic field and an antiferromagnetic coupling to the adjacent thicker Co layers, whose magnetization direction is dominated by the applied magnetic field. With specimens whose Cu spacer-layer thickness is 9 A(ring) (i.e., at the first antiferromagnetic maximum) the dependence of total magnetization on applied magnetic field reveals the different behavior of the two types of Co layer. This behavior may be exploited to obtain materials with reduced magnetoresistive hysteresis at the second antiferromagnetic maximum (i.e., with Cu spacer thickness of 20 A(ring)) by combining the large magnetoresistance of Co layers with thicknesses ∼15 A(ring) with the small hysteresis of Co layers with thicknesses ∼3 A(ring). © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 7395-7397 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The dependence of the magnetoresistive properties of Co/Cu multilayers on the thickness of the Co layers is described for the case when the Cu layer thickness is 9 A(ring), corresponding to the first antiferromagnetic maximum. Both the width and the height of the peaks in the magnetoresistance/field curves decrease with increasing Co layer thickness in the range 5–50 A(ring). This leads to an optimum Co layer thickness of 30–40 A(ring) that maximizes the sensitivity to changes in magnetic field. This result may have practical significance for applications that require the relative lack of hysteresis that is found at the first antiferromagnetic maximum. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We describe the dependence of magnetoresistance and magnetoresistive hysteresis upon the Co layer thickness in Co/Cu multilayers with Cu layer thickness equal to 20 A(ring), i.e., at the second antiferromagnetic maximum. When the Co layer thickness is reduced to 3 A(ring) the magnetoresistive hysteresis disappears. The elimination of hysteresis is accompanied by a decrease of magnetoresistance, but the sensitivity to changes in the magnetic field is only reduced by a factor of 2. This result makes available the larger sensitivity of the second antiferromagnetic maximum to applications that are adversely affected by hysteresis. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 782-789 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We describe the structural and magnetoresistive properties of Ag-Co and Ag-Ni granular alloys that were grown epitaxially on MgO{100} substrates. With substrate temperatures in the range 300–400 °C and up to 25 vol% of the ferromagnetic constituent (Co or Ni) x-ray analyses showed that the Ag matrices were elastically strained (by stretching at the interface with the substrate), but had relaxed lattice constants that were the same as that of pure Ag. This excludes the possibility of significant amounts of dissolved Co or Ni. The Co and Ni precipitates gave lattice spacings that were consistent with somewhat smaller strains. Growth at 200 °C appears to yield only partial precipitation of the Co or Ni, as judged by a 20% reduction in saturation magnetization from the values obtained with growth at 300–400 °C. Replacement of Co by Ni in otherwise similar alloys causes an increase in the size of the ferromagnetic precipitates. This leads to a decrease in surface area that combines with a decrease in saturation magnetization to give substantially smaller magnetoresistance in Ag-Ni than in Ag-Co. With both alloy systems, decrease of the substrate temperature leads to decreased precipitate size whose influence is seen in the magnitude of the magnetoresistance, the temperature dependence of the hysteresis, and the rate of approach to saturation with applied magnetic field. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 82 (1997), S. 322-325 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Co1−xCux/Cu multilayers have been made by sputtering using codeposition of Co and Cu to obtain Co1−xCux alloy layers that are separated by 20 Å Cu spacers. As with Co/Cu multilayers, this Cu spacer thickness corresponds to the second antiferromagnetic maximum. At ambient temperatures, the Co1−xCux/Cu multilayers with x(approximate)0.5 exhibit an absence of magnetoresistive hysteresis resembling that reported previously for Co/Cu multilayers at the second antiferromagnetic maximum when the Co layers are very thin (∼3 Å). The multilayers with Co1−xCux alloys differ significantly from the low-hysteresis Co/Cu multilayers by exhibiting low hysteresis over a larger range of ferromagnetic layer thickness. This is practically significant because it reduces the demands for thickness control during manufacturing. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Measurements of structure and magnetoresistance in Ag-Co0.4Ni0.6 granular alloy films with 10–23.5 vol % Co0.4Ni0.6 grown epitaxially on MgO{100} are reported. These results elucidate the effects of varying both the concentration and the size of the Co0.4Ni0.6 precipitates in the Ag matrix. It is shown that the magnetic-field-dependent contribution to the resistivity, Δρmag, is consistent with the predictions of a two-current model in which spin-dependent scattering is dominated by the interfaces between the precipitates and the matrix. Specifically we observe: (a) A regime where Δρmag is linear in c/D, with c the volume fraction of precipitates with diameter D. (b) Extrapolation of these linear dependences to Δρmag=0 gives values of 1/D that are proportional to 1/c. (c) With D(approximately-greater-than)100 A(ring) there is a reduced dependence on particle size that is consistent with transition to a quadratic dependence. In contrast, at the lower concentrations the behavior of the maximum resistivity, ρmax, is not well described by the two-current model that suffices for Δρmag. This suggests that refinement of the model may be needed for granular films that have relatively large and widely spaced ferromagnetic precipitates. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: This investigation reports the effect of dilute additions of ozone in molecular oxygen on the limiting reactive gas pressures required for in situ deposition of YBa2Cu3O7−x thin films. Thermodynamic analysis indicates that the high oxidizing potential of ozone assures stability at equilibrium under virtually all experimental conditions of ozone pressure and substrate temperature. Thus the generation of a minor fraction of ozone in oxygen enables in situ deposition to be carried out without further enrichment at gas pressures well below those required in pure molecular oxygen. In situ superconductor deposition at various rates using coevaporated metals revealed a lower limit at an ozone-to-copper ratio of approximately unity. Superconducting films deposited at O3/Cu flux ratios above this threshold were highly (00l) oriented with critical temperatures of 87–90 K and critical currents of 2×106 A/cm2 that exhibited only small or ambiguous trends with increasing ozone above the threshold. Films deposited at O3/Cu ratios below the threshold were visually dissimilar (transparent-brown), semiconducting, and marked by conspicuous disappearance of the characteristic x-ray spectra. This threshold is a nonthermodynamic limit below which the supply of ozone is insufficient to maintain stoichiometry during continuous deposition. Since ozone molecules donate only single oxygen atoms in reaction, the observed limiting O3/Cu flux ratio supplies no more than one-half the total oxygen required to form tetragonal YBa2Cu3O6, which is the entry level phase for in situ deposition. It follows that molecular oxygen continues to function as a principal oxidant in reactive deposition even at reduced operating pressures given the stabilizing presence of ozone at a sufficient flux to elevate copper to its higher oxidation state.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...