Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Galvanomagnetic voltages in the vicinity of a domain wall in ferromagnetic thin films (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 1550-1555 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Ferromagnetic Ni-Fe films of thickness 〈85 nm contain Néel or crosstie walls, with wall thickness as large as 6 μm. Because of the anisotropic magnetoresistance Δρ/ρ0(approximately-equal-to)2% in Ni-Fe, the electrical resistivity is slightly larger inside a wall than in the adjacent domains, for currents normal to the wall. This should result in a detectable increase dV of the ohmic voltage between two miniature potential probes when a wall is located between them. For reasonable values of the dc current density, our calculations predict dV(approximately-equal-to)9 μV per wall. When the current is parallel to Néel walls, there should be a local decrease of the resistivity inside each wall, manifested as a decrease of the average sample resistance. This effect seems to provide an explanation for the upward resistance jumps observed in Ni-Fe magnetoresistive reading heads when Néel walls disappear. Also, because of the planar Hall effect, a voltage V should appear between two potential probes when one probe is located at the wall center.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.347248
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Current-induced displacements and precession of a Bloch wall in Ni-Fe thin films : 37th Annual conference on magnetism and magnetic materials (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 6405-6407 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Rectangular or exponential current pulses of duration (approximately-equal-to)0.1 μs traversing a Bloch wall are found to induce wall displacements Δx≤10 μm/pulse in a Ni81Fe19 film of thickness (approximately-equal-to)263 nm. The critical current density for wall displacement is jc(approximately-equal-to)1.35×106 A/cm2, about 20–200 times lower than for Néel or cross-tie walls investigated earlier. Wall motion arises probably from the precession of wall spins under the influence of the "s-d exchange torque'' exerted by conduction electrons crossing the wall. The low jc value and easy precession of spins in a Bloch wall reflect the very small value (approximately-equal-to)300 μT of the wall demagnetizing field which opposes spin orientation out of the wall plane in films of this thickness. A dc in-plane hard-axis field causes a linear decrease of jc. A dc easy-axis field smaller than Hc produces only a very slow decrease of jc.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.352611
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Observation of galvanomagnetic voltages at a magnetic domain wall in Ni-Fe films : The 5th Joint MMM−Intermag Conference (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 5825-5827 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A Ni81Fe19 film of 110 nm thickness is traversed by a dc current density normal to the easy axis. Two sharp tungsten wires serve as potential probes, distant by 210 μm along the easy axis. A charged wall, oriented at an angle to the easy axis, is made to creep slowly across the sample by applying dc easy axis and 60-Hz hard axis magnetic fields. The dc voltage between the probes is found to vary whenever the wall passes by the probes. The variation has the form of a voltage peak of (approximately-equal-to)40 μV typical height. These peaks are caused by the planar Hall effect, in combination with a canting of the domain magnetization near the charged wall. In the case of a current parallel to the easy axis and normal to the line joining the probes, a steplike voltage variation ≤150 μV is observed for an uncharged wall in the presence of a dc hard axis field. Planar Hall effect and (field induced) domain canting are again responsible.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.350123
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Theory of magnetoresistance in concentrated ferromagnetic alloys (invited) (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 5549-5554 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Existing values of the magnetoresistance (ρ(parallel)−ρ⊥)/ρ0 for crystalline Ni1−xFex, Ni1−xCox, Ni1−xMnx, Fe1−xCrx, and Fe1−x-Vx alloys depend on x in a way which disagrees with the traditional Smit theory, based on the Born approximation. The reasons are related to the variation of the 3d wave-function amplitude between chemically different atoms and, in turn, to a variation of s-d scattering intensity. Experimental atomic moments indicate that this 3d amplitude variation is large. The variation is related to the fact that d-d scattering is strong and resonant. We predict large deviations from Nordheim's rule ρ↓∝ x(1−x) where ρ↓ is the spin-down resistivity, similar to the deviations found experimentally. Correspondingly, (ρ(parallel)−ρ⊥)/ρ0 is much larger for x(approximately-equal-to)0 than for x(approximately-equal-to)1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.345882
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Prediction of Shapiro steps in the dc voltage across a magnetic domain wall traversed by a dc current and exposed to high-frequency magnetic fields : 35th Annual conference on magnetism and magnetic materials (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 4683-4685 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In metallic ferromagnets, a current of electrons traversing a domain wall exerts a torque on the wall spins through the s-d exchange interaction. This torque may induce a precession of the wall spins around the easy axis. In turn, the wall precession at a rate ω0 generates a dc voltage δV across the wall, given by the formula eδV = (h-dash-bar)ω0 similar to the Josephson equation for superconducting junctions. In the present theoretical work, a high-frequency (hf), in-plane, hard-axis magnetic field is also applied. For a certain range of values of the dc current density, the rate of wall precession is synchronous with that of the hf drive field. In other ranges, precession is asynchronous, or there is no precession. As a result, the voltage δV has a stepwise dependence on the current density. This is the analog of the well-known Shapiro steps for the superconducting Josephson voltage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.348296
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Motion of a magnetic domain wall traversed by fast-rising current pulses (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 2721-2726 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A Bloch wall is predicted to undergo finite displacements when traversed by a current pulse with short rise time ≤20 ns and long fall time, in thin films of metallic ferromagnets. In Ni–Fe films of thickness 85–150 nm, pulses with peak current density (approximately-equal-to)1×107 A/cm2 are expected to induce wall displacements of order 0.1–1 μm. This effect originates from the s-d exchange interaction. It is phenomenologically similar to the well-known "wall streaming'' motion of Bloch walls subjected to fast-rising pulses of hard-axis magnetic field. The effect is related to the existence of a novel, current-induced, term in the expression for the momentum of a magnetic domain wall.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.351045
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Domain walls in ferromagnetic nanoconstriction (2002)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 5341-5346 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: 180° domain walls in ferromagnetic nanoconstrictions are investigated by classical atomic Monte Carlo simulations. Two types of constrictions are considered; one is a uniform circular cylinder (isthmus), the other is a double-truncated cone (hour glass). The wall width is determined by the effective length of the constriction, which may be as little as a nanometer. The wall can have a Néel-like configuration for constrictions much narrower than the normal wall width, but there is a crossover region with vortex-type walls before reaching a Bloch-type wall at larger diameters. In very narrow constrictions, effects of the atomic-scale structure become evident as the domain-wall structure depends on the number of atoms in the cross section. The simulations confirm the prospect of creating very narrow domain walls in a nanoconstricted soft magnetic material, and they indicate the possibility of spontaneous thermal fluctuations between different magnetic modes in walls smaller than about 10 nm. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1461065
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    New origin for spin current and current-induced spin precession in magnetic multilayers (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 89 (2001), S. 5521-5525 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In metallic ferromagnets, an electric current is accompanied by a flux of angular momentum, also called spin current. In multilayers, spatial variations of the spin current correspond to drive torques exerted on a magnetic layer. These torques result in spin precession above a certain current threshold. The usual kind of spin current is associated with translation of the spin-up and spin-down Fermi surfaces in momentum space. We discuss a different kind of spin current, associated with expansion and contraction of the Fermi surfaces. It is more nonlocal in nature, and may exist even in locations where the electrical current density is zero. It is larger than the usual spin current, in a ratio of 10 or 100, at least in the case of one-dimensional current flow. The new spin current is proportional to the difference Δμ¯(similar, equals)10−3 eV between spin-up and spin-down Fermi levels, averaged over the entire Fermi surface. Conduction processes, spin relaxation, and spin-wave emission in the multilayer can be described by an equivalent electrical circuit resembling an unbalanced dc Wheatstone bridge. And Δμ¯ corresponds to the output voltage of the bridge. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1365080
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    A Dimorphic Form of d-Catechin (1946)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 68 (1946), S. 145-146 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja01205a510
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Current-induced displacements of Bloch walls in Ni-Fe films of thickness 120–740 nm (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 4787-4792 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Rectangular current pulses of duration 0.14 μs, flowing across Bloch domain walls in Ni81Fe19 films, cause displacements Δx of these walls, observable by Kerr-contrast microscopy. In zero magnetic field, Δx reaches (approximately-equal-to)14 μm/pulse at current densities (approximately-equal-to)30% above the value jc where wall motion starts. This critical current density is jc(approximately-equal-to)1.2×1010 A/m2 for a film thickness w=263 nm. We have measured jc versus film thickness for w=120–740 nm, and find jc∝w−2.1. This suggests strongly that the observed wall motion is associated with an S-shaped distortion of the wall by the circumferential magnetic field of the current. This wall distortion is limited by the wall surface tension. The wall structure becomes that of the so-called asymmetric Néel wall. Through wall distortion, the current pulse pumps kinetic energy and momentum into the wall. This kinetic energy is then dissipated during ballistic wall motion happening largely after the end of the pulse. We also find jc to be independent of pulse duration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.357250
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...