Lattice thermal conductivity of compounds with inhomogeneous intermediate rare-earth ion valence

2002 ◽  
Vol 44 (6) ◽  
pp. 1031-1034 ◽  
Author(s):  
A. V. Golubkov ◽  
L. S. Parfen’eva ◽  
I. A. Smirnov ◽  
H. Misiorek ◽  
J. Mucha ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Rare Earth ◽  
Lattice Thermal Conductivity ◽  
Rare Earth Ion

scholarly journals Substantial thermal conductivity reduction in mischmetal skutterudites MmxCo4Sb12 prepared under high-pressure conditions, due to uneven distribution of the rare-earth elements

2019 ◽  
Vol 7 (14) ◽  
pp. 4124-4131 ◽  
Author(s):  
J. Gainza ◽  
F. Serrano-Sánchez ◽  
J. Prado-Gonjal ◽  
N. M. Nemes ◽  
N. Biskup ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
High Pressure ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Lattice Thermal Conductivity ◽  
Low Cost ◽  
Uneven Distribution ◽  
Filling Fraction ◽  
The Rare Earth

Low-cost n-type Mischmetal-filled CoSb3 skutterudites with elemental filling-fraction separation, prepared at high pressure, exhibit markedly low lattice thermal conductivity.

How cerium filling fraction influences thermal factors and magnetism in CeyFe4-xNixSb12.

2000 ◽  
Vol 626 ◽  
Author(s):  
L. Chapon ◽  
D. Ravot ◽  
J.C. Tedenac ◽  
F. Bouree-Vigneron
Keyword(s):  
Thermal Conductivity ◽  
Rare Earth ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Theoretical Calculations ◽  
Filling Fraction ◽  
Rare Earth Atom ◽  
Filled Skutterudites ◽  
Order Of Magnitude ◽  
Mass Fluctuation

Since few years, cerium filled and partially filled skutterudites are intensively studied because they show a wide variety of fundamental and applied properties. One of them consists in high values of thermal factors for rare earth atom in antimony skutterudites [1,2]. Slack suggests [3,4] a incoherent rattling of this ion in the oversized cage “Sb12” surrounding the cerium which affects highly the phonon motion and thus lowers the lattice thermal conductivity (kl). As a rule, the lattice thermal conductivity is decreased by a factor of 5 or greater by filling entirely the voids of the binary filled skutterudites with rare earth atoms [5]. Besides, kl decreases for partially filled compounds in respect with totally filled ones [6,7]. Mass fluctuation mechanism between cerium atom and vacancy is obviously involved as the origin of this last reduction. On that purpose, theoretical calculations [7] demonstrate that the reduction belonging to mass fluctuation mechanism is an order of magnitude lower than the measured decrease. As the mass fluctuation added to the “rattling” on the cerium site is not sufficient to explain such low values of thermal conductivity, another phonon scattering mechanism must exist. In order to find another mechanism we present the influence of the filling fraction of cerium on thermal factors and the temperature dependence of this factor for a partially filled compound.

The effect of rare-earth filling on the lattice thermal conductivity of skutterudites

1996 ◽  
Vol 79 (8) ◽  
pp. 4002 ◽  
Author(s):  
G. S. Nolas ◽  
G. A. Slack ◽  
D. T. Morelli ◽  
T. M. Tritt ◽  
A. C. Ehrlich
Keyword(s):  
Thermal Conductivity ◽  
Rare Earth ◽  
Lattice Thermal Conductivity

scholarly journals Charting Lattice Thermal Conductivity for Inorganic Crystals and Discovering Rare Earth Chalcogenides for Thermoelectrics

2021 ◽  
Author(s):  
Taishan Zhu ◽  
Ran He ◽  
Sheng Gong ◽  
Tian Xie ◽  
Prashun Gorai ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Rare Earth ◽  
Thermoelectric Materials ◽  
Lattice Thermal Conductivity ◽  
Energy Landscape ◽  
Promising Candidate ◽  
Low Thermal Conductivity ◽  
Inorganic Crystals ◽  
The Future

Thermoelectricity produced from usually negative-valued heat is a green and promising candidate on the future energy landscape. The most effective thermoelectric materials exhibit low thermal conductivity κ. However, less than...

scholarly journals Strongly reduced lattice thermal conductivity in Sn-doped rare-earth (M) filled skutterudites MxCo4Sb12−ySny, promoted by Sb–Sn disordering and phase segregation

RSC Advances ◽  
2021 ◽  
Vol 11 (42) ◽  
pp. 26421-26431
Author(s):  
J. Gainza ◽  
F. Serrano-Sánchez ◽  
N. M. Nemes ◽  
O. J. Dura ◽  
J. L. Martínez ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Rare Earth ◽  
Carrier Density ◽  
Lattice Thermal Conductivity ◽  
Phase Segregation ◽  
Intrinsic Disorder ◽  
Filling Fraction ◽  
Filled Skutterudites ◽  
Sn Substitution ◽  
The Way

Three effects act as phonon scatterers: rattling of M at 8a cages, phase segregation, and intrinsic disorder introduced by Sn substitution, resulting in minimum k values. High filling fraction in Sn-doped phases pave the way to tune the carrier density in skutterudites.

Dislocation-induced ultra-low lattice thermal conductivity in rare earth doped β-Zn4Sb3

2020 ◽  
Vol 174 ◽  
pp. 95-101 ◽  
Author(s):  
Vaithinathan Karthikeyan ◽  
Clement Manohar Arava ◽  
May Zin Hlaing ◽  
Baojie Chen ◽  
Chi Hou Chan ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Rare Earth ◽  
Lattice Thermal Conductivity ◽  
Rare Earth Doped

Lattice Thermal Conductivity Modelling of a Diatomic Nanoscale Material

2020 ◽  
Vol 10 (5) ◽  
pp. 602-609
Author(s):  
Adil H. Awad
Keyword(s):  
Thermal Conductivity ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Correction Term ◽  
Nanoscale Material ◽  
New Approach ◽  
Two Samples ◽  
Conductivity Modelling ◽  
Callaway Model

Introduction: A new approach for expressing the lattice thermal conductivity of diatomic nanoscale materials is developed. Methods: The lattice thermal conductivity of two samples of GaAs nanobeam at 4-100K is calculated on the basis of monatomic dispersion relation. Phonons are scattered by nanobeam boundaries, point defects and other phonons via normal and Umklapp processes. Methods: A comparative study of the results of the present analysis and those obtained using Callaway formula is performed. We clearly demonstrate the importance of the utilised scattering mechanisms in lattice thermal conductivity by addressing the separate role of the phonon scattering relaxation rate. The formulas derived from the correction term are also presented, and their difference from Callaway model is evident. Furthermore their percentage contribution is sufficiently small to be neglected in calculating lattice thermal conductivity. Conclusion: Our model is successfully used to correlate the predicted lattice thermal conductivity with that of the experimental observation.

scholarly journals Local ferroelectric polarization switching driven by nanoscale distortions in thermoelectric $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aastha Vasdev ◽  
Moinak Dutta ◽  
Shivam Mishra ◽  
Veerpal Kaur ◽  
Harleen Kaur ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Lattice Thermal Conductivity ◽  
Direct Evidence ◽  
Temperature Dependent ◽  
Force Microscopy ◽  
Ferroelectric Domains ◽  
Pdf Analysis ◽  
Ferroelectric Transition Temperature

AbstractA remarkable decrease in the lattice thermal conductivity and enhancement of thermoelectric figure of merit were recently observed in rock-salt cubic SnTe, when doped with germanium (Ge). Primarily, based on theoretical analysis, the decrease in lattice thermal conductivity was attributed to local ferroelectric fluctuations induced softening of the optical phonons which may strongly scatter the heat carrying acoustic phonons. Although the previous structural analysis indicated that the local ferroelectric transition temperature would be near room temperature in $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te , a direct evidence of local ferroelectricity remained elusive. Here we report a direct evidence of local nanoscale ferroelectric domains and their switching in $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te using piezoeresponse force microscopy(PFM) and switching spectroscopy over a range of temperatures near the room temperature. From temperature dependent (250–300 K) synchrotron X-ray pair distribution function (PDF) analysis, we show the presence of local off-centering distortion of Ge along the rhombohedral direction in global cubic $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te . The length scale of the $${\text {Ge}}^{2+}$$ Ge 2 + off-centering is 0.25–0.10 Å near the room temperatures (250–300 K). This local emphatic behaviour of cation is the cause for the observed local ferroelectric instability, thereby low lattice thermal conductivity in $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te .

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