Das thermische Rauschen

Bittel, Heinz; Storm, Leo

doi:10.1007/978-3-642-49240-2_2

Cited by 5 publications

(8 citation statements)

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“…a result already obtained by Bittel and Storm (1971) among others. The integration shows that for frequencies ω below l/τ the Fourier cosine transform is frequency independent, for intermediate frequencies up to s max /x it is 1/f and for the highest frequencies it is 1/f 2 .…”

Section: Ln(l + T/t 0 )supporting

confidence: 80%

Boson Mediated Relaxation in Solids

McQueen¹,

Kubát²

2000

Journal of the Mechanical Behavior of Materials

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Dielectric and mechanical relaxation in solids, characterised by non-exponential, extended relaxation spectra, is analysed taking the interaction of the phonon (boson) field with the relaxing elements in the solid explicitly into account. Combination of Einstein's rate equations with Bothe's analysis of boson clustering results in a second order non-linear rate equation for the relaxing elements.The character of the solutions of this equation is governed by the strength and frequency dependence of the interaction of the phonons with the relaxing elements. The upper frequency limit is the Debye cutoff frequency while the lower frequency limit is determined by grain boundaries or the like.Relaxations extending over four decades of time are obtained using physically realistic parameters.Fourier transformation produces a 1/f spectrum over a correspondingly wide frequency range. These results are compatible with experimental results concerning stress relaxation in solids and with the "universal dielectric response" of dipoles in condensed matter.Brought to you by | Purdue University Libraries Authenticated Download Date | 5/27/15 2:19 PM well illustrated in Li plots. This is a consequence of the fact that the phonon spectra of the solids can vary somewhat as well as can the details of how the applied mechanical stress moves the relaxing elements to their excited states.Finally, we have shown that the results obtained here are compatible with results obtained by Ngai, Jonscher and Kubät, among others.

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Section: Ln(l + T/t 0 )supporting

confidence: 80%

Boson Mediated Relaxation in Solids

McQueen¹,

Kubát²

2000

Journal of the Mechanical Behavior of Materials

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“…The same result is obtained if the calculations are performed with a Fermi gas instead of a simple electron gas [18].…”

Section: F Grüneissupporting

confidence: 78%

“…The first term is further developed under the assumptions made for a simple electron gas (= Drude model [17,18]). Applying the equipartition theorem to the x-component of velocity fluctuations, we obtain…”

Section: The Power Spectral Density For Intermittent Phonon Scatterinmentioning

confidence: 99%

Intermittent Phonon Scattering as a Possible Origin of 1/f Fluctuations in Metallic Resistors

Grüneis

2015

Fluct. Noise Lett.

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We regard a metallic resistor for temperatures T Θ D (= Debye temperature); under this condition, electron-phonon scattering is the dominant scattering mechanism. We investigate the noise properties under the supposition that phonon scattering is an intermittent process. Intermissions may be caused by an interaction between different phonon modes giving rise to a short break down of a mode. Due to such an intermittent behavior, we obtain -besides thermal noise -a 1/f noise component. Under equilibrium conditions, the 1/f noise term disappears. Under an applied electric field, the electrons are accelerated between collisions resulting in an additional 1/f noise component which can be compared with Hooge's relation. The predicted Hooge coefficient is α ≈ 3 · 10 −3 (τ off /τs) 2 with τs being the mean electron phonon scattering time and τ off being the mean off-time (= intermission). We also find 1/f fluctuations in the square of thermal noise suggesting that an applied current only probes 1/f fluctuations which are already present under equilibrium conditions.

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“…by molecules hitting the cathode surface. For a tungsten cathode operated in the saturation mode m is about 2 (60). With decreasing frequency the second term increases proportional to {2 which e.g.…”

Section: Influence Of Topographymentioning

confidence: 95%

“…With decreasing frequency the second term increases proportional to {2 which e.g. leads to a doubling of at frequencies of typically 0.1 Hz (60). For low emission currents and a clean vacuum, where the impingement rate of molecules at the cathode is low, the onset of flicker noise contributions shifts towards lower frequencies (10-2 to 10- 3 As total measurement times in the SEM usually are in the range of less than 100 s the contributions of flicker noise can be neglected here.…”

Section: Influence Of Topographymentioning

confidence: 99%