From ballistic to non-ballistic magnetoresistance in nanocontacts: theory and experiments

Zhao, Yibing; Muñoz, Manuel; Tatara, Gen; Garcı́a, N.

doi:10.1016/s0304-8853(00)00750-2

Cited by 17 publications

(17 citation statements)

References 16 publications

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“…Extending these ideas to a wider variety of materials including alloys, amorphous metals, perovskites and Heusler alloys it is possible to discern a pattern of sorts. Zhao et al defined a parameter they call the ballisticity b = D/ℓ sf , where ℓ sf is called the "mean free path for spin reversal (ballistic non-adiabatic limit)" [317] and D is the wall thickness. This quantity was estimated from the vari-ation of conductance with contact size, and as a result contacts classified as either ballistic (1/b ≫ 1) or non-ballistic (b ≫ 1).…”

Section: First Resultsmentioning

confidence: 99%

Spin-polarised currents and magnetic domain walls

Marrows

2005

Advances in Physics

213

163

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Electrical currents flowing in ferromagnetic materials are spinpolarised as a result of the spin-dependent band structure. When the spatial direction of the polarisation changes, in a domain structure, the electrons must somehow accommodate the necessary change in direction of their spin angular momentum as they pass through the wall. Reflection, scattering, and a transfer of angular momentum to the lattice are all possible outcomes, depending on the circumstances. This gives rise to a variety of different physical effects, most importantly a contribution to the electrical resistance caused by the wall, and a motion of the wall driven by the spin-polarised current.Historical and recent research on these topics is reviewed. * Phone: +44(0)113 3433780

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Section: First Resultsmentioning

confidence: 99%

Spin-polarised currents and magnetic domain walls

Marrows

2005

Advances in Physics

213

163

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“…22 In dirty contacts, the effect is not so large, since the wall scattering is smeared out by impurity scattering. 32 Hard magnets with strong magnetic anisotropy, e.g. materials containing rareearth like SmCo 5 and manganese perovskites, are also suitable to study the domain wall resistance.…”

Section: Domain Wall Contribution To Classical Magnetoresistancementioning

confidence: 99%

“…22 In contrast in disordered case the effect in the limit of thin wall is not as large as in the ballistic case. 32 Although the last equality of Eq. (37) is true only when |σ c |/σ 0 1, the result of Eq.…”

Section: Disordered Casementioning

confidence: 99%

Domain Wall Resistivity Based on a Linear Response Theory

Tatara

2001

Int. J. Mod. Phys. B

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The resistivity due to a domain wall in a ferromagnetic metal is calculated based on a linear response theory. The scattering by impurities is taken into account. The electronwall interaction is derived from the exchange interaction between the conduction electron and the magnetization by use of a local gauge transformation in the spin space. This interaction is treated perturbatively to the second order. The classical (Boltzmann) contribution from the wall scattering turns out to be negligiblly small if the wall is thick compared with the fermi wavelength. In small contacts a large classical domain wall resistance is expected due to a thin wall trapped in the constriction. In the dirty case, where quantum coherence among electrons becomes important at low temperature, spin flip scattering caused by the wall results in dephasing and hence suppresses weak localization. Thus the quantum correction due to the wall can lead to a decrease of resistivity. This effect grows rapidly at low temperature where the wall becomes the dominant source of dephasing. Conductance change in the quantum region caused by the motion of the wall is also calculated. Int. J. Mod. Phys. B 2001.15:321-371. Downloaded from www.worldscientific.com by YALE UNIVERSITY on 02/04/15. For personal use only. b It becomes essential in discussing the dynamics of the magnetization such as the tunneling of the chirality, φ. 56,57 c The effect of conduction electron on the wall structure was discussed in Ref. 58. Int. J. Mod. Phys. B 2001.15:321-371. Downloaded from www.worldscientific.com by YALE UNIVERSITY on 02/04/15. For personal use only.

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“…Very recently, we learned about a calculation by Zhao et al 33 of the resistance of a domain wall at a point contact in the diffusive limit. Using our Eq.…”

Section: Importance Of Random Scatteringmentioning

confidence: 99%

Analysis of measured transport properties of domain walls in magnetic nanowires and films

Berger

2006

Phys. Rev. B

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Existing data for soft magnetic materials of critical current for domain-wall motion, wall speed driven by a magnetic field, and wall electrical resistance show that all three observable properties are related through a single parameter: the wall mobility . The reciprocal of represents the strength of viscous friction between domain wall and conduction-electron gas. And is a function of the wall width, which depends in turn on the aspect ratio t / w, where t and w are the thickness and width of the sample. Over four orders of magnitude of , the data for nanowires show ϰ ͑t / w͒ −2.2 . This dependence is in approximate agreement with the prediction of the 1984 Berger theory based on s-d exchange. On the other hand, it is inconsistent with the prediction of the

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From ballistic to non-ballistic magnetoresistance in nanocontacts: theory and experiments

Cited by 17 publications

References 16 publications

Spin-polarised currents and magnetic domain walls

Spin-polarised currents and magnetic domain walls

Domain Wall Resistivity Based on a Linear Response Theory

Analysis of measured transport properties of domain walls in magnetic nanowires and films

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