Quantitative "local-interference" model for<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mfrac><mml:mrow><mml:mn>1</mml:mn></mml:mrow><mml:mrow><mml:mi>f</mml:mi></mml:mrow></mml:mfrac></mml:math>noise in metal films

Pelz, J. P.; Clarke, John

doi:10.1103/physrevb.36.4479

Cited by 100 publications

(61 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These processes takes place on a length scale typical of the spacing between neighboring defects l e hence, the induced noise is called ''local interference'' noise. 48 The local interference processes do not vary with small magnetic fields. A crude way of accounting for the mixture of local interference and long-range interference ͑i.e., UCF͒ noise in our samples is to add an extra fitting parameter called the ''fraction UCF'', or f UCF .…”

Section: /F Noise and Universal Conductance Fluctuationsmentioning

confidence: 99%

Experimental comparison of the phase-breaking lengths in weak localization and universal conductance fluctuations

1999

View full text Add to dashboard Cite

The observation of quantum transport phenomena in metals is limited by the eventual loss of phase coherence of the conduction electrons on the length scale L . We address the question of whether L is the same in the context of different quantum transport phenomena. Specifically, we have measured L from two different experiments on the same sample. The experiments are magnetoresistance and 1/f noise versus magnetic field, and the samples are thin-Ag films in the quasi-two-dimensional regime. We determine L from fits of the magnetoresistance data to weak-localization theory ͑WL͒, and from fits of the noise versus magnetic field to universal conductance fluctuation theory ͑UCF͒. We find that the two values of L are the same at temperatures above about 10 K, but that L in the UCF experiment is shorter than that in the WL experiment at lower temperatures. This result is consistent with a recent theoretical discussion of quasielastic electron-electron scattering in disordered metals. ͓S0163-1829͑99͒00132-0͔

show abstract

Section: /F Noise and Universal Conductance Fluctuationsmentioning

confidence: 99%

Experimental comparison of the phase-breaking lengths in weak localization and universal conductance fluctuations

1999

View full text Add to dashboard Cite

show abstract

“…In disordered metallic systems these fluctuations, often known as 1/f -noise, are extremely sensitive to slow relaxation of defects (dislocations, cluster of point defects etc). Random movement of the scatterers, even at a scale ∼ Fermi wavelength (λ F < ∼ 1 nm), change the interference pattern of coherently back-scattered electrons, reflecting in the time-dependent fluctuations in the resistivity [15]. In magnetic systems, the DWs themselves can act as scatterers of spinpolarized conduction electrons, and modify the R of the nanowires.…”

mentioning

confidence: 99%

Tracking Random Walk of Individual Domain Walls in Cylindrical Nanomagnets with Resistance Noise

2010

View full text Add to dashboard Cite

The stochasticity of domain wall (DW) motion in magnetic nanowires has been probed by measuring slow fluctuations, or noise, in electrical resistance at small magnetic fields. By controlled injection of DWs into isolated cylindrical nanowires of nickel, we have been able to track the motion of the DWs between the electrical leads by discrete steps in the resistance. Closer inspection of the time-dependence of noise reveals a diffusive random walk of the DWs with an universal kinetic exponent. Our experiments outline a method with which electrical resistance is able to detect the kinetic state of the DWs inside the nanowires, which can be useful in DW-based memory designs.

show abstract

“…To account for field-independent local interference noise [31,32] at higher temperatures, a second fitting parameter, z, the fraction of noise that is due to UCF, was introduced into the fitting function, f (B) = (1 − z) + zν(B). We found that z was indistinguishable from 1 for all temperatures measured except for 20 K in the 2d samples, when z ≈ 0.68.…”

mentioning

confidence: 99%

Electronic coherence in metals: Comparing weak localization and time-dependent conductance fluctuations

2004

View full text Add to dashboard Cite

Quantum corrections to the conductivity allow experimental assessment of electronic coherence in metals. We consider whether independent measurements of different corrections are quantitatively consistent, particularly in systems with spin-orbit or magnetic impurity scattering. We report weak localization and time-dependent universal conductance fluctuation data in quasi-one-and two-dimensional AuPd wires between 2 K and 20 K. The data inferred from both methods are in excellent quantitative agreement, implying that precisely the same coherence length is relevant to both corrections. 72.70.+m,73.20.Fz Quantum coherence of electrons in solids remains a topic of much interest. Technologically, coherent control and manipulation of electrons is relevant in proposed novel devices [1,2]. Scientifically, the mechanisms and temperature dependence of decoherence are of fundamental importance [3], and have profound implications for the ground state of metals in the presence of disorder. Quantum corrections to the conductivity allow coherence to be examined experimentally. Specific corrections that have been used include the weak localization (WL) magnetoresistance[4], universal conductance fluctuations as a function of magnetic field [5,6] (MFUCF), time-dependent universal conductance fluctuations (TDUCF) [7,8], and Aharonov-Bohm oscillations [9].These corrections result from interference between electronic trajectories on length scales shorter than the coherence length, L φ ≡ Dτ φ , where D is the electron diffusion constant and τ φ is the timescale over which the phase of the electron's wave function is perturbed strongly by environmental degrees of freedom. It is interesting to ask whether precisely the same time (length) scales are relevant to the various quantum corrections. For example, the electron "out-scattering" time (for scattering out of a particular momentum state) in the Boltzmann equation with screened Coulomb interactions has a different temperature dependence[10] than the coherence time for weak localization [3,11], and has been suggested as relevant to UCF [12]. One must also consider whether other complications (e.g. spin-orbit coupling; scattering from dilute magnetic impurities) affect the inferred values of L φ identically. Subtleties are known to exist regarding magnetic impurities in Aharonov-Bohm rings [13]. These questions have particular relevance as recent publications concerning saturation Weak localization results from electron trajectories that form closed loops, and their time-reversed conjugates. With no spin-orbit scattering and at zero magnetic field, such pairs constructively interfere, leading to a lowered conductance. Strong spin-orbit interactions lead instead to destructive interference, and a conductance increase at zero magnetic field. Magnetic flux through such a loop suppresses these interference effects, resulting in a magnetoresistance with a field scale that reflects L WL φ and the sample geometry. Time-dependent UCF result from changes in defects' positions that alter the...

show abstract

Quantitative "local-interference" model for1fnoise in metal films

Cited by 100 publications

References 15 publications

Experimental comparison of the phase-breaking lengths in weak localization and universal conductance fluctuations

Experimental comparison of the phase-breaking lengths in weak localization and universal conductance fluctuations

Tracking Random Walk of Individual Domain Walls in Cylindrical Nanomagnets with Resistance Noise

Electronic coherence in metals: Comparing weak localization and time-dependent conductance fluctuations

Contact Info

Product

Resources

About