Substitution versus full-Heusler segregation in TiCoSb

Research output: Contribution to journalArticle

Abstract

Half-Heuslers (HHs) are promising thermoelectric materials with great compositional flexibility. Here, we extend work on the p-type doping of TiCoSb using abundant elements. Ti0.7V0.3Co0.85Fe0.15Sb0.7Sn0.3 samples with nominal 17.85 p-type electron count were investigated. Samples prepared using powder metallurgy have negative Seebeck values, S ≤ -120 µV K-1, while arc-melted compositions are compensated semiconductors with S = -45 to +30 µV K-1. The difference in thermoelectric response is caused by variations in the degree of segregation of V(Co0.6Fe0.4)2Sn full-Heusler and Sn phases, which selectively absorb V, Fe, and Sn. The segregated microstructure leads to reduced lattice thermal conductivities, κlat = 4.5-7 W m-1 K-1 near room temperature. The largest power factor, S2/ρ = 0.4 mW m-1 K-2 and ZT = 0.06, is observed for the n-type samples at 800 K. This works extends knowledge regarding suitable p-type dopants for TiCoSb.
LanguageEnglish
Article number935
JournalMetals
Volume8
Issue number11
DOIs
Publication statusPublished - 12 Nov 2018

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substitutes
thermoelectric materials
powder metallurgy
flexibility
thermal conductivity
arcs
microstructure
room temperature
electrons

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title = "Substitution versus full-Heusler segregation in TiCoSb",
abstract = "Half-Heuslers (HHs) are promising thermoelectric materials with great compositional flexibility. Here, we extend work on the p-type doping of TiCoSb using abundant elements. Ti0.7V0.3Co0.85Fe0.15Sb0.7Sn0.3 samples with nominal 17.85 p-type electron count were investigated. Samples prepared using powder metallurgy have negative Seebeck values, S ≤ -120 µV K-1, while arc-melted compositions are compensated semiconductors with S = -45 to +30 µV K-1. The difference in thermoelectric response is caused by variations in the degree of segregation of V(Co0.6Fe0.4)2Sn full-Heusler and Sn phases, which selectively absorb V, Fe, and Sn. The segregated microstructure leads to reduced lattice thermal conductivities, κlat = 4.5-7 W m-1 K-1 near room temperature. The largest power factor, S2/ρ = 0.4 mW m-1 K-2 and ZT = 0.06, is observed for the n-type samples at 800 K. This works extends knowledge regarding suitable p-type dopants for TiCoSb.",
author = "Maryana Asaad and Jim Buckman and Bos, {Jan-Willem G.}",
year = "2018",
month = "11",
day = "12",
doi = "10.3390/met8110935",
language = "English",
volume = "8",
journal = "Metals",
issn = "2075-4701",
publisher = "MDPI AG",
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}

Substitution versus full-Heusler segregation in TiCoSb. / Asaad, Maryana; Buckman, Jim; Bos, Jan-Willem G.

In: Metals, Vol. 8, No. 11, 935, 12.11.2018.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Substitution versus full-Heusler segregation in TiCoSb

AU - Asaad, Maryana

AU - Buckman, Jim

AU - Bos, Jan-Willem G.

PY - 2018/11/12

Y1 - 2018/11/12

N2 - Half-Heuslers (HHs) are promising thermoelectric materials with great compositional flexibility. Here, we extend work on the p-type doping of TiCoSb using abundant elements. Ti0.7V0.3Co0.85Fe0.15Sb0.7Sn0.3 samples with nominal 17.85 p-type electron count were investigated. Samples prepared using powder metallurgy have negative Seebeck values, S ≤ -120 µV K-1, while arc-melted compositions are compensated semiconductors with S = -45 to +30 µV K-1. The difference in thermoelectric response is caused by variations in the degree of segregation of V(Co0.6Fe0.4)2Sn full-Heusler and Sn phases, which selectively absorb V, Fe, and Sn. The segregated microstructure leads to reduced lattice thermal conductivities, κlat = 4.5-7 W m-1 K-1 near room temperature. The largest power factor, S2/ρ = 0.4 mW m-1 K-2 and ZT = 0.06, is observed for the n-type samples at 800 K. This works extends knowledge regarding suitable p-type dopants for TiCoSb.

AB - Half-Heuslers (HHs) are promising thermoelectric materials with great compositional flexibility. Here, we extend work on the p-type doping of TiCoSb using abundant elements. Ti0.7V0.3Co0.85Fe0.15Sb0.7Sn0.3 samples with nominal 17.85 p-type electron count were investigated. Samples prepared using powder metallurgy have negative Seebeck values, S ≤ -120 µV K-1, while arc-melted compositions are compensated semiconductors with S = -45 to +30 µV K-1. The difference in thermoelectric response is caused by variations in the degree of segregation of V(Co0.6Fe0.4)2Sn full-Heusler and Sn phases, which selectively absorb V, Fe, and Sn. The segregated microstructure leads to reduced lattice thermal conductivities, κlat = 4.5-7 W m-1 K-1 near room temperature. The largest power factor, S2/ρ = 0.4 mW m-1 K-2 and ZT = 0.06, is observed for the n-type samples at 800 K. This works extends knowledge regarding suitable p-type dopants for TiCoSb.

U2 - 10.3390/met8110935

DO - 10.3390/met8110935

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JO - Metals

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