Effect of chromium disorder on the thermoelectric properties of Layered-antiferromagnet CuCrS2

Tewari, Girish C.; Tripathi, T. S.; Rastogi, A. K.

doi:10.1524/zkri.2010.1313

Cited by 20 publications

(52 citation statements)

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“…XPS gives the Cr-vacancy [Cr(I)] disorder in the magnetic layers as well as their occupancy in the empty layers [Cr(II)] for all the compounds, in agreement with previously reported refinement data of XRD patterns of the same compounds. 10 The high-temperature treatment increases both the disorder and ZT. The increase in ZT is simultaneous with increase in the electrical conductivity due to self-doping of carriers and reduction of thermal conductivity due to increase in the defect concentration, while keeping S reasonably high in the paramagnetic phase of these layered antiferromagnets.…”

Section: Discussionmentioning

confidence: 99%

“…The XPS results regarding the concentrations of Cr(I) and Cr(II) species are in close agreement with the previous XRD refinement results. 10 …”

Section: X-ray Photoelectron Spectroscopymentioning

confidence: 99%

“…3, from our earlier publication. 10 The upper panel shows the resistivity of polycrystalline samples 1(700°C), 2a(900°C), and 2b(900°C), while the lower panel shows q of a crystal flake. The room-temperature q of samples 2a/2b(900°C) are 10 mX-cm and 6 mX-cm, respectively, and of crystal flake, 8 mX-cm, being considerably lower than the value of $2 X-cm for sample 1(700°C) prepared at comparatively lower temperature.…”

Section: Electrical Resistivitymentioning

confidence: 99%

“…This behavior has been explained as due to hopping conduction of polarons in the paramagnetic phase that gives a large and saturating thermoelectric power at high temperature. 9,10 The large thermoelectric power along with low electrical resistivity around room temperature make these compounds potential candidates for TE applications. …”

Section: Thermoelectric Powermentioning

confidence: 99%

“…At high temperature, disorder increases and more chromium atoms are transferred from layers to vacant interlayer sites, which causes dramatic reduction of the electrical resistivity q compared to the low-temperature phase, while S remains high. 10 Herein we report the results of x-ray photoelectron spectroscopy (XPS) at room temperature. Analysis of the XPS spectra verifies our earlier findings based on XRD study.…”

Section: Introductionmentioning

confidence: 99%

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Increase in the Thermoelectric Efficiency of the Disordered Phase of Layered Antiferromagnetic CuCrS2

Tewari

Tripathi

Kumar

et al. 2011

Journal of Elec Materi

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The thermoelectric figure of merit (ZT) of the layered antiferromagnetic compound CuCrS 2 is further improved with increase in the Cr-vacancy disorder on sintering above 900°C. X-ray photoelectron spectroscopy and x-ray diffraction refinement results for different samples show that the chromium atoms are transferred from the filled layers to the vacant sites between the layers. This atomic disorder increases the electrical conductivity (r) due to self-doping of the charge carriers and reduces thermal conductivity (j) due to increase in phonon scattering. The Seebeck coefficient (S) is p-type and remains nearly temperature independent with values between 150 lV/K and 450 lV/K due to electronic doping in different samples.

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Section: Discussionmentioning

confidence: 99%

“…The XPS results regarding the concentrations of Cr(I) and Cr(II) species are in close agreement with the previous XRD refinement results. 10 …”

Section: X-ray Photoelectron Spectroscopymentioning

confidence: 99%

Section: Electrical Resistivitymentioning

confidence: 99%

Section: Thermoelectric Powermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Increase in the Thermoelectric Efficiency of the Disordered Phase of Layered Antiferromagnetic CuCrS2

Tewari

Tripathi

Kumar

et al. 2011

Journal of Elec Materi

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Does Low‐Level Substitution Aid in Improving Thermoelectric Properties? A Case Study of M_0.1Ni_0.9Cr₂S₄ (M = Mn, In)

et al. 2021

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Recent interest in renewable, sustainable concepts for energy production led to an increasing spotlight on thermoelectric materials, being an environmentally friendly means of continuous power generation from waste heat. Established and wellresearched materials with high efficiencies such as Sb 2 Te 3 , [1][2][3][4] Bi 2 Te 3 , [1][2][3][4] or PbTe [5][6][7] generally suffer from low abundance of the included elements, cost-inefficiency and environmental issues, which ultimately inhibit their large-scale applicability. An alternative exists in chromium sulfides, [8][9][10] whose thermoelectric properties have already been reported in the 1960s: [8] the high abundance of Cr and S as well as a reasonable environmental footprint make them promising candidates, even though their initial efficiency appears lower than in established materials. [11] In turn, their compositional flexibility and variability of the crystal structures allow for a plethora of possibilities to improve and tune their thermoelectric properties. Exemplary performances have, for example, been achieved with CuCrS2, which appeared highly suitable for thermoelectric applications and exhibited performances very similar to the established tellurides. [12][13][14][15] Structurally similar, but less investigated is NiCr 2 S 4 , which appears as a so-called ordered defect phase. [16,17] The thermoelectric properties of this material depend highly on the order and occupation of cations in their defect layers, which can subsequently be manipulated to affect conduction properties as well as the material's phase. Furthermore, it has been reported that layered chromium sulfides generally retain their pristine structure while being doped or

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Tunable Low‐Temperature Thermoelectric Transport Properties in Layered CuCr(S_1‐xSe_x)₂ System

Tewari

Kousar

Srivastava

et al. 2023

Zeitschrift anorg allge chemie

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We have characterized the layered CuCr(S,Se)2 system for the spin‐polarized electronic band structures and low‐temperature thermoelectric transport properties. The electronic band structure calculations reveal semiconducting behavior for CuCrS2, CuCr(S0.5Se0.5)2 and CuCrSe2 with an indirect bandgap of 0.42, 0.30 and 0.10 eV, respectively. The systematically decreased bandgap with increasing Se content is in line with the experimental observations showing a semiconductor‐to‐metal transition with increasing Se‐substitution level in the CuCr(S1‐xSex)2 system because of an increase in the charge carrier density. The p‐type Seebeck coefficient shows a linear temperature dependence for the samples, like in degenerate semiconductors or metals. The remarkably large Seebeck coefficient even in metallic samples is due to a relatively large effective mass of charge carriers. As the thermal conductivity is intrinsically low owing to the layered crystal structure and is further decreased for the Se‐substituted samples because of the increased phonon scattering from point defects, the thermoelectric characteristics are promising. The highest dimensionless figure‐of‐merit values were seen for the x=0.5 sample, e. g., 0.04 at 400 K.

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Effect of chromium disorder on the thermoelectric properties of Layered-antiferromagnet CuCrS2

Cited by 20 publications

References 5 publications

Increase in the Thermoelectric Efficiency of the Disordered Phase of Layered Antiferromagnetic CuCrS2

Increase in the Thermoelectric Efficiency of the Disordered Phase of Layered Antiferromagnetic CuCrS2

Does Low‐Level Substitution Aid in Improving Thermoelectric Properties? A Case Study of M_0.1Ni_0.9Cr₂S₄ (M = Mn, In)

Tunable Low‐Temperature Thermoelectric Transport Properties in Layered CuCr(S_1‐xSe_x)₂ System

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Effect of chromium disorder on the thermoelectric properties of Layered-antiferromagnet CuCrS2

Cited by 20 publications

References 5 publications

Increase in the Thermoelectric Efficiency of the Disordered Phase of Layered Antiferromagnetic CuCrS2

Increase in the Thermoelectric Efficiency of the Disordered Phase of Layered Antiferromagnetic CuCrS2

Does Low‐Level Substitution Aid in Improving Thermoelectric Properties? A Case Study of M0.1Ni0.9Cr2S4 (M = Mn, In)

Tunable Low‐Temperature Thermoelectric Transport Properties in Layered CuCr(S1‐xSex)2 System

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Product

Resources

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Does Low‐Level Substitution Aid in Improving Thermoelectric Properties? A Case Study of M_0.1Ni_0.9Cr₂S₄ (M = Mn, In)

Tunable Low‐Temperature Thermoelectric Transport Properties in Layered CuCr(S_1‐xSe_x)₂ System