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

Nolas, George S.; Slack, Glen A.; Morelli, Donald T.; Tritt, Terry M.; Ehrlich, A. C.

doi:10.1063/1.361828

Cited by 421 publications

(226 citation statements)

References 38 publications

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“…16 Even further reductions have been reported in multi-filled compounds where two or more elements are used as rattler atoms. 7,[17][18][19][20][21][22][23][24] The larger reductions in the thermal conductivity in the thermal conductivity of multi-compared to single-filled materials is attributed to the scattering of a broader range of host lattice phonon frequencies due to the rattlers of the different elements vibrating at different frequencies. In a recent contribution 25 on the study of rattling in the Al-doped β-pyrochlores, AAl0.33W1.67O6 (A = K, Rb, Cs), we reported the discovery of novel rattling of K atoms in KAl0.33W1.67O6 involving both vibrations at a broad range of frequencies as well as local diffusion.…”

Section: Introductionmentioning

confidence: 99%

Novel K rattling: A new route to thermoelectric materials?

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Kearley

Peterson

et al. 2014

Journal of Applied Physics

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We have performed ab initio molecular dynamics (MD) simulations to study the alkali-metal dynamics in the Al-doped (KAl0.33W1.67O6 and RbAl0.33W1.67O6) and undoped (KW2O6 and RbW2O6) defect pyrochlore tungstates. The K atoms exhibit novel rattling dynamics in both the doped and undoped tungstates while the Rb atoms do not. The KAl0.33W1.67O6 experimental thermal conductivity curve shows an unusual depression between ~ 50 K and ~ 250 K, coinciding with two crossovers in the K dynamics: the first at ~ 50 K, from oscillatory to diffusive, and the second at ~ 250 K, from diffusive back to oscillatory. We found that the low-temperature crossover is a result of the system transitioning below the activation energy of the diffusive dynamics whereas the high-temperature crossover is driven by a complex reconstruction of the local potential around the K atoms due to the cage dynamics.This leads to a hardening of the K potential with increasing temperature. This unusual reconstruction of the potential may have important implications for the interpretation of finite-temperature dynamics based on zero-temperature potentials in similar materials. The key result is that the novel K rattling, involving local diffusion, leads to a significant reduction in the thermal conductivity. We suggest that this may open a new route in the phonon engineering of cage compounds for thermoelectric materials where the rattlers are specifically selected to reduce the lattice thermal conductivity by the mechanism of local diffusion. a)

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Section: Introductionmentioning

confidence: 99%

Novel K rattling: A new route to thermoelectric materials?

Shoko

Kearley

Peterson

et al. 2014

Journal of Applied Physics

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“…In these materials, a significant depression of the lattice thermal conductivity (thus becoming glass-like with short phonon mean free paths) is due to pronounced scattering of heat-carrying phonons, despite the fact that these compounds are well crystallized with long-range atomic order. This is caused by an intricate interplay between filler atoms and the host structure [13,14]. On the other hand, due to their ordered structure, these materials conduct electricity like a crystal with long electron mean free paths.…”

Section: Introductionmentioning

confidence: 99%

Application of spark plasma sintering to the fabrication of binary and ternary skutterudites

Recknagel

Reinfried

Höhn

et al. 2007

Science and Technology of Advanced Materials

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Spark plasma sintering (SPS) synthesis of CoSb 3 and LaFe 4 Sb 12 from ball-milled elemental metal powders has been performed obtaining samples with high relative densities ($99%). Fracture behaviour, the microstructure and mechanical properties were studied. From ultrasound and nano-indentation measurements, Young's moduli of 148 GPa for CoSb 3 and 141 GPa for LaFe 4 Sb 12 were deduced. SPS has been also applied to compact alkali metal and alkaline-earth metal iron antimonides with filled skutterudite structure. r

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“…However, the broad maximum is found even in polycrystalline filled skutterudites, where defects are expected to be plentiful. [3] A shoulder in κ(T ) is found only in skutterudites with small filler atoms, [3,16] whose large amplitude rattling leads to particularly strong phonon scattering. The shoulder observed in κ(T ) in CaFe 4 As 3 implies that the phonon scattering is very strong here as well.…”

Section: Resultsmentioning

confidence: 99%

Thermal and electrical transport in the spin density wave antiferromagnet CaFe4As3

et al. 2011

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We present here measurements of the thermopower, thermal conductivity, and electrical resistivity of the newly reported compound CaFe4As3. Evidence is presented from specific heat and electrical resistivity measurements that a substantial fraction of the Fermi surface survives the onset of spin density wave (SDW) order at the Néel temperature TN=88 K, and its subsequent commensurate lockin transition at T2=26.4 K. The specific heat below T2 consists of a normal metallic component from the ungapped parts of the Fermi surface, and a Bardeen-Cooper-Schrieffer (BCS) component that represents the SDW gapping of the Fermi surface. A large Kadowaki-Woods ratio is found at low temperatures, showing that the ground state of CaFe4As3 is a strongly interacting Fermi liquid. The thermal conductivity κ of CaFe4As3 is an order of magnitude smaller than those of conventional metals at all temperatures, due to a strong phonon scattering. The thermoelectric power S displays a sign change from positive to negative indicating that a partial gap forms at the Fermi level with the onset of commensurate spin density wave order at T2 = 26.4 K. The small value of the thermopower S and the enhancements of the resistivity due to gap formation and strong quasiparticle interactions offset the low value of the thermal conductivity κ, yielding only a modest value for the thermoelectric figure of merit Z ≤ 5 × 10The results of ab initio electronic structure calculations are reported, confirming that the sign change in the thermopower at T2 is reflected by a sign change in the slope of the density of states at the Fermi level. Values for the quasiparticle renormalization Z are derived from measurements of the specific heat and thermopower, indicating that as T → 0, CaFe4As3 is among the most strongly correlated of the known Fe-based pnictide and chalcogenide systems.

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

Cited by 421 publications

References 38 publications

Novel K rattling: A new route to thermoelectric materials?

Novel K rattling: A new route to thermoelectric materials?

Application of spark plasma sintering to the fabrication of binary and ternary skutterudites

Thermal and electrical transport in the spin density wave antiferromagnet CaFe4As3

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