Phonon damping in thin films of Fe

Röhlsberger, Ralf; Sturhahn, W.; Toellner, T. S.; Quast, K. W.; Hession, P.; Hu, Michael Y.; Sutter, John P.; E., E.

doi:10.1063/1.370770

Cited by 50 publications

(37 citation statements)

References 13 publications

(15 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(i) The decrease in intensity of high-energy modes (15 and 18 meV) was observed before in various nanoscale systems 12,13,16,19,[21][22][23][24][25] , an effect which was found to originate from phonon scattering. From the TEM study, it was concluded that a single Sn island is composed of many Sn crystallites.…”

Section: B Phonon Density Of Statesmentioning

confidence: 79%

“…The phonon density of states (PDOS) of low dimensional systems is expected to be modified due to the restriction of phonon propagation [7][8][9][10][11] . Previously, clear differences between the phonon density of states of bulk and that of nanostructures have been observed, with as most commonly observed anomalies in the phonon spectra of nanostructures: an enhancement of low-energy modes, appearance of high-energy modes above the cut-off energy of the bulk material and a broadening of the PDOS features [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] . For thin films, the broadening of features in the PDOS was attributed to phonon damping 13,19,27,28 and the enhancement of low-energy phonon modes due to the appearance of surface modes 14,19,27 .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Lattice dynamics in Sn nanoislands and cluster-assembled films

et al. 2017

View full text Add to dashboard Cite

To unravel the effects of phonon confinement, the influence of size and morphology on the atomic vibrations is investigated in Sn nano islands and cluster-assembled films. Nuclear resonant inelastic X-ray scattering is used to probe the phonon density of states of the Sn nanostructures which show significant broadening of the features compared to bulk phonon behaviour. Supported by ab initio calculations, the broadening is attributed to phonon scattering and can be described within the damped harmonic oscillator model. Contrary to the expectations based on previous research, the appearance of high-energy modes above the cut-off energy is not observed. From the thermodynamic properties extracted from the phonon density of states, it was found that grain boundary Sn atoms are bound by weaker forces than bulk Sn atoms.

show abstract

Section: B Phonon Density Of Statesmentioning

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Lattice dynamics in Sn nanoislands and cluster-assembled films

et al. 2017

View full text Add to dashboard Cite

show abstract

“…[62][63][64][65][66] Such a shift could reduce the probability of the largeangle phonon scattering events required to return L (T ) to the Sommerfeld value at high T, thereby requiring higher temperatures to finally reenter the WF regime. However, our calculations suggest that the shifts in phonon DOS required to explain the ∼ 20% reduction in L seen here are so large that they would drive deviations of the heat capacity away from bulk-like values, in contrast to experimental data showing very good agreement between bulk and even very thin Au and Cu films.…”

Section: -47mentioning

confidence: 99%

Thermal and electrical conductivity of approximately 100-nm permalloy, Ni, Co, Al, and Cu films and examination of the Wiedemann-Franz Law

et al. 2015

View full text Add to dashboard Cite

We present measurements of thermal and electrical conductivity of polycrystalline permalloy (Ni-Fe), aluminum, copper, cobalt, and nickel thin films with thickness < 200 nm. A micromachined silicon-nitride membrane thermal isolation platform allows measurements of both transport properties on a single film and an accurate probe of the Wiedemann-Franz (WF) law expected to relate the two. Through careful elimination of possible effects of surface scattering of phonons in the supporting membrane, we find excellent agreement with WF in a thin Ni-Fe film over nearly the entire temperature range from 77 to 325 K. All other materials studied here deviate somewhat from the WF prediction of electronic thermal conductivity with a Lorenz number, L, suppressed from the free-electron value by 10 − 20%. For Al and Cu we compare the results to predictions of the theoretical expression for the Lorenz number as a function of T . This comparison indicates two different types of deviation from expected behavior. In the Cu film, a higher than expected L at lower T indicates an additional thermal conduction mechanism, while at higher T lower than expected values suggests an additional inelastic scattering mechanism for electrons. We suggest the additional low T L indicates a phonon contribution to thermal conductivity, and consider increased electron-phonon scattering at grain boundaries or surfaces to explain the high T reduction in L.

show abstract

“…Another source of reduction in the phonon lifetime originates from a smaller grain size. The DHO model has been used to describe size effects in metal nanostructures 29,30 . Indeed, the lifetime in nanostructures is expected to decrease due to the smaller mean-free-path induced by the smaller crystallite size.…”

Section: B Nuclear Inelastic Scatteringmentioning

confidence: 99%

Interplay between lattice dynamics and superconductivity in Nb3Sn thin films

et al. 2013

Self Cite

View full text Add to dashboard Cite

We investigate the link between superconductivity and atomic vibrations in Nb3Sn films with a thickness ranging from 10 to 50 nm. The challenge of measuring the phonon density of states of these films has been tackled by employing the technique of nuclear inelastic scattering by 119 Sn isotopes to reveal the Sn-partial phonon density of states. With the support of ab initio calculations, we evaluate the effect of reduced film thickness on the PDOS. This approach allows us to estimate the changes in superconducting critical temperature Tc induced by phonon confinement, which turned out to be limited to a few tenths of K. The presented method is successful for the Nb3Sn system and paves the way for more systematic studies of the role of phonon confinement in Sn-containing superconductors.2

show abstract

Phonon damping in thin films of Fe

Cited by 50 publications

References 13 publications

Lattice dynamics in Sn nanoislands and cluster-assembled films

Lattice dynamics in Sn nanoislands and cluster-assembled films

Thermal and electrical conductivity of approximately 100-nm permalloy, Ni, Co, Al, and Cu films and examination of the Wiedemann-Franz Law

Interplay between lattice dynamics and superconductivity in Nb3Sn thin films

Contact Info

Product

Resources

About