The thermal conductivity of dielectric crystals: the effect of isotopes

Berman, R.; Foster, E.L.; Ziman, John

doi:10.1098/rspa.1956.0181

Cited by 86 publications

(8 citation statements)

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“…We show the first observation of transverse SSE response, which might solve the controversial question of whether or not a true TSSE exists in metallic FM films. [41] 25 [42] 135 for Si [39] ; 2 to 5 for SiN [40] …”

Section: T(cold)]mentioning

confidence: 99%

Optical detection of transverse spin-Seebeck effect in permalloy film using Sagnac interferometer microscopy

et al. 2017

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Macroscopic spatially spin distribution caused by the application of an in-plane thermal gradient in a conducting ferromagnetic film, known as transverse spin-Seebeck effect (TSSE), is in many cases overshadowed by thermoelectric and magneto-thermoelectric effects when using the conventional electrical detection via the inverse spin Hall effect.Here we report an optical method for the detection and characterization of TSSE response in permalloy films using magneto-optical Kerr effect with an ultrasensitive fiber-optic Sagnac interferometer microscope that is free of magneto-thermoelectric artefacts, which also allows measurements with field direction parallel and perpendicular to the film surface. We found a substantial anisotropy in the permalloy TSSE coefficient, where the 'in-plane magnetization' coefficient is much larger than that in the 'out-of-plane magnetization'. †These authors contributed equally to this work. *To whom correspondence should be addressed: val@physics.utah.edu ‡ Current address: Department of Physics, North Carolina State University, Raleigh, NC, 27695,The young field of 'Spin Caloritronics' seeks to exploit the strong coupling between spin currents and heat currents with application opportunities in novel devices [1,2]. It has been shown that a temperature gradient in a ferromagnetic (FM) metal [3,4] and alloys [5], FM semiconductor [6,7], or FM insulator [8][9][10][11][12][13][14] in the presence of a magnetic field B spontaneously generates a position-dependent accumulation of spin-polarized carriers that forms spin current (J S ) in an adjacent non-magnetic overlayer; this was dubbed the spin-Seebeck effect (SSE) [2].The SSE has been shown to exist even in the paramagnetic phase above the FM phase-transition temperature in some cases [15,16]. Among the spin caloritronics processes, longitudinal SSE response (LSSE, where J S is parallel to the direction of thermal gradient) in magnetic insulators have been extensively studied [9][10][11][12][13][14], whereas attempts to measure the transverse SSE response (TSSE, where J S is perpendicular to the direction of thermal gradient) [3,[6][7][8] have raised a number of questions [17][18][19][20][21]. In particular, the steady state TSSE in conducting FM films has not been thoroughly explored.So far the SSE has been exclusively detected by depositing onto the FM film a "spin-detection layer" that consists of a non-magnetic metal (NM) having strong spin-orbit coupling (SOC) such as Pt, which converts the spin current in the FM layer into charge current in the NM overlayer via the inverse spin Hall effect (ISHE) [3]. We note, however that the ISHE voltage that is used to detect the SSE in the FM substrate is quite small (of the order of several μV/K) and phenomenologically similar to a number of thermoelectric and magneto-thermoelectric artefacts such as the regular Seebeck effect, the proximity/anomalous/planar Nernst effect and the LSSE induced by an unintentional out-of-plane thermal gradient [17][18][19][20][21]. Therefore it has be...

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Section: T(cold)]mentioning

confidence: 99%

Optical detection of transverse spin-Seebeck effect in permalloy film using Sagnac interferometer microscopy

et al. 2017

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“…Specifically, if each solid solution compound contains p distinct crystallographic sub-lattice sites and several different ions, j, can occupy each of these sites, the mass disorder is related to the concentration of the different ions on each crystallographic site and the scattering cross-section is given by the expression [23], [24], [25]: (4) where n is the total number of atoms in the unit cell, ni is the number of atoms on the sub-lattice, i, is the mean mass of the unit cell, is the mean mass on the i-th sub-lattice and is the phonon scattering coefficient from mass variance on the i-th sub-lattice. The variance of the masses on each sub-lattice, in effect the "mass disorder", in equation In addition to the effects of phonon scattering from point defects, the thermal conductivity also scales as the inverse square root of the mean atomic mass of the compound [26].…”

Section: Discussionmentioning

confidence: 99%

Thermal conductivity of single- and multi-phase compositions in the ZrO2–Y2O3–Ta2O5 system

Limarga

Shian

Leckie

et al. 2014

Journal of the European Ceramic Society

117

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Compositions in the ZrO2-Y2O3-Ta2O5 system are of interest as low thermal conductivity, fracture resistant oxides for the next generation thermal barrier coatings (TBC). Multiple phases occur in the system offering the opportunity to compare the thermal properties of single, two-phase, and three-phase materials. Despite rather large variations in compositions almost all the solid solution compounds had rather similar thermal conductivities and, furthermore, exhibited only relatively small variations with temperature up to 1000 o C. These characteristics are attributed to the extensive mass disorder in all the compounds and, in turn, small interfacial Kapitza (thermal) resistances. More complicated behavior, associated with the transformation from the tetragonal to monoclinic phase, occurs on long-term annealing in air of some of the compositions. However, the phases in two of the compositional regions do not change with annealing in air and their thermal conductivities remain unchanged suggesting they may be suitable for further exploration as thermally stable TBC overcoats.

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“…The properties of TiO 2 nanostructures vary substantially with the synthesis method [42] and large collections of studies and achievements have been reported regarding their electrical and thermal properties and how they are influenced by various TiO 2 nanostructures. Berman and Forster [43] conducted measurements on the thermal conductivity of several dielectric crystals including TiO 2 rutile. They concluded that limitations in the isotopic species of the chemical elements in the crystal caused it to behave differently from the Peierls predicted thermal conductivity curve for perfect crystals.…”

Section: Introductionmentioning

confidence: 99%

Thermal conductivity and secondary porosity of single anatase TiO₂nanowire

2012

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Single anatase TiO₂ nanowire is synthesized using the electrospinning technique with the sol-gel method and is suspended over a pre-processed 100 µm-wide TEM grid for further characterization. The diameters of the nanowires fall in the range of 250-400 nm. The transient electrothermal (TET) method is adopted to acquire the voltage-time (U-t) profile of the Ir-coated nanowire under step Joule heating. The intrinsic thermal diffusivity of single anatase TiO₂ nanowires varies from 1.3 to 4.6 × 10⁻⁶ m² s⁻¹, and the thermal conductivity changes distinctly from 1.3 to 5.6 W m⁻¹ K⁻¹, much lower than the value of the bulk counterpart: 8.5 W m⁻¹ K⁻¹. The density and thermal conductivity increase significantly with the diameter, largely because at larger diameters less secondary porosity is left by decomposition of organic composites and their escape from the wire during calcination. The density of TiO₂ nanowires is found to be much lower than that of the bulk counterpart. This is supported by the SEM image of the secondary porous surface. High secondary porosity is observed for TiO₂ nanowires, ranging from 18% to 63%. This very high secondary porosity confirms that the decomposition of PVP content may distort the fibrous matrix and leave vacancies. In addition, the transition from amorphous to anatase phase could also create a porous state due to crystal particle aggregation.

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The thermal conductivity of dielectric crystals: the effect of isotopes

Cited by 86 publications

References 4 publications

Optical detection of transverse spin-Seebeck effect in permalloy film using Sagnac interferometer microscopy

Optical detection of transverse spin-Seebeck effect in permalloy film using Sagnac interferometer microscopy

Thermal conductivity of single- and multi-phase compositions in the ZrO2–Y2O3–Ta2O5 system

Thermal conductivity and secondary porosity of single anatase TiO₂nanowire

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The thermal conductivity of dielectric crystals: the effect of isotopes

Cited by 86 publications

References 4 publications

Optical detection of transverse spin-Seebeck effect in permalloy film using Sagnac interferometer microscopy

Optical detection of transverse spin-Seebeck effect in permalloy film using Sagnac interferometer microscopy

Thermal conductivity of single- and multi-phase compositions in the ZrO2–Y2O3–Ta2O5 system

Thermal conductivity and secondary porosity of single anatase TiO2nanowire

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Thermal conductivity and secondary porosity of single anatase TiO₂nanowire