Advances in Studying Phonon Mean Free Path Dependent Contributions to Thermal Conductivity

Regner, Keith T.; Freedman, Justin P.; Malen, Jonathan A.

doi:10.1080/15567265.2015.1045640

Cited by 59 publications

(42 citation statements)

References 97 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, typical codes describe only diffusive heat transport, ignoring ballistic or quasi-ballistic phonon transport that is known to play a role in nanoscale metallic features on insulating substrates [43]. In fact the previously common view that only phonons of quite short wavelength and mean-free-path dominate heat transport in bulk materials at room temperature is now understood to be incorrect, with more and more quantitative measurements showing large contributions to heat flow from parts of the phonon spectrum ignored in typical FEM simulations [32,[44][45][46][47][48]. These issues suggest that truly quantitative determination of the SDSE coefficient will be challenging and some level of disagreement between experimental groups should be expected, a situation familiar to the spintronics community.…”

Section: Discussionmentioning

confidence: 99%

Thermal spin injection and interface insensitivity in permalloy/aluminum metallic nonlocal spin valves

2016

View full text Add to dashboard Cite

We present measurements of thermal and electrical spin injection in nanoscale metallic non-local spin valve (NLSV) structures. Informed by measurements of the Seebeck coefficient and thermal conductivity of representative films made using a micromachined Si-N thermal isolation platform, we use simple analytical and finite element thermal models to determine limits on the thermal gradient driving thermal spin injection and calculate the spin dependent Seebeck coefficient to be −0.5 µV/K < S s < −1.6 µV/K. This is comparable in terms of the fraction of the absolute Seebeck coefficient to previous results, despite dramatically smaller electrical spin injection signals.Since the small electrical spin signals are likely caused by interfacial effects, we conclude that thermal spin injection is less sensitive to the FM/NM interface, and possibly benefits from a layer of oxidized ferromagnet, which further stimulates interest in thermal spin injection for applications in sensors and pure spin current sources.1 arXiv:1602.03859v2 [cond-mat.mes-hall]

show abstract

Section: Discussionmentioning

confidence: 99%

Thermal spin injection and interface insensitivity in permalloy/aluminum metallic nonlocal spin valves

2016

View full text Add to dashboard Cite

show abstract

“…Thus, in order to ensure efficient operational performance of these devices, the unwanted heat generated needs to be rapidly dissipated. The possession of high thermal conductivity is essential for effective dissipation of heat to enable the optimum performance temperature of devices to be kept at very low levels so as to eliminate dielectric degradation caused by overheating (Ngo and Byon 2015, Reddy et al 2015, Regner et al 2016. Hence, the enhancement of heat dissipation abilities of materials used in these sensitive devices has become very crucial (Lee et al 2012a,b).…”

Section: Introductionmentioning

confidence: 98%

“…The effective transfer of heat in modern medical devices, photonics, optoelectronics, computer/electronics, and integrated circuits (ICs) has become crucial for superior reliability and performance of these devices (Miranda and Yang 2015, Nomura et al 2015, Regner et al 2016, Gu et al 2016. The rapid escalation of power densities in three-dimensional (3D) integration and highpower density communication, information, and energy storage devices has made thermal management of these devices critically essential (Renteria et al 2015a).…”

Section: Introductionmentioning

confidence: 99%

Recently emerging trends in thermal conductivity of polymer nanocomposites

Idumah

Hassan²

2016

Reviews in Chemical Engineering

View full text Add to dashboard Cite

Due to escalating power densities in electronics, information, communication, energy storage, aerospace, and automobile technologies, heat dissipation has become immensely essential for the efficient performance and reliability of photonic, electronics, optoelectronics, and other devices in order to proactively prevent premature failure due to overheating. The functionalization and synergistic inclusion of thermally conducting nanoparticles such as carbon derivatives and metallic and ceramic fillers into polymer matrices have resulted in development of thermally conducting polymer nanocomposites. This has enlarged the scope of application of these materials in areas hitherto restricted due to poor thermal conductivity and, therefore, opened broad windows of opportunities for polymer nanocomposites as emerging alternative replacements for metal components in various applications where effective heat dissipation is compulsory for device performance. Thus, this paper critically discusses globally emerging technologies applied in the development of thermally conductive polymer nanocomposites for various industrial applications.

show abstract

“…As discussed by several recent works [17,[30][31][32][33], we relate the changing thermal penetration depth with the varying frequency during a TDTR experiments to changes in the net heat flux. Thus, we modify our EMA modeling approach to separate the thermal conductivity of the samples into a high frequency mode component (diffusive) and low frequency mode component (quasi-ballistic).…”

mentioning

confidence: 99%

Ballistic transport of long wavelength phonons and thermal conductivity accumulation in nanograined silicon-germanium alloys

Chen

Braun

Donovan

et al. 2017

Applied Physics Letters

View full text Add to dashboard Cite

Computationally efficient modeling of the thermal conductivity of materials is crucial to thorough experimental planning and theoretical understanding of thermal properties. We present a modeling approach in this work that utilizes frequency-dependent effective medium to calculate lattice thermal conductivity of nanostructured solids. The method accurately predicts a significant reduction in the thermal conductivity of nanostructured Si 80 Ge 20 systems, along with previous reported thermal conductivities in nanowires and nanoparticles-in-matrix materials. We use our model to gain insight into the role of long wavelength phonons on the thermal conductivity of nanograined silicon-germanium alloys. Through thermal conductivity accumulation calculations with our modified effective medium model, we show that phonons with wavelengths much greater than the average grain size will not be impacted by grain boundary scattering, counter to the traditionally assumed notion that grain boundaries in solids will act as diffusive interfaces that will limit long wavelength phonon transport. This is further supported through a modulation frequency dependent thermal conductivity as measured with time-domain thermoreflectance.

show abstract

Advances in Studying Phonon Mean Free Path Dependent Contributions to Thermal Conductivity

Cited by 59 publications

References 97 publications

Thermal spin injection and interface insensitivity in permalloy/aluminum metallic nonlocal spin valves

Thermal spin injection and interface insensitivity in permalloy/aluminum metallic nonlocal spin valves

Recently emerging trends in thermal conductivity of polymer nanocomposites

Ballistic transport of long wavelength phonons and thermal conductivity accumulation in nanograined silicon-germanium alloys

Contact Info

Product

Resources

About