Thermoelectric properties of layer-antiferromagnet CuCrS2

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Researchers

Research units

  • Jawaharlal Nehru University

Abstract

We have performed a detailed study of the electrical and thermal conductivities and thermoelectric power behavior of an antiferromagnetic-layer compound of chromium, CuCrS 2, from 15 K to 300 K. Unlike previous studies, we find noninsulating properties and sensitive dependence on the preparation method, the microstructure, and the flaky texture formed in polycrystalline samples after extended sintering at high temperatures. Flakes are found to be metallic, with strong localization effects in the conductivity on cooling to low temperatures. The antiferromagnetic transition temperature T N (=40 K) remains essentially unaffected. The Seebeck coefficient is found to be in the range of 150 æV/K to 450 æV/K, which is exceptionally large, and becomes temperature independent at high temperatures, even for specimens with low resistivity values of 5 mê cm to 200 mê cm. We find the thermal conductivity κ to be low, viz. 5 mW/K cm to 30 mW/K cm. This can be attributed mostly to the dominance of lattice conduction over electronic conduction. The value of κ is further reduced by disorder in Cu occupancy in the quenched phase. We also observe an unusually strong dip in κ at T N, which is probably due to strong magnetocrystalline coupling in these compounds. Finally we discuss the properties of CuCrS 2 as a heavily doped Kondo-like insulator in its paramagnetic phase. The combination of the electronic properties observed in CuCrS 2 makes it a potential candidate for various thermoelectric applications.

Details

Original languageEnglish
Pages (from-to)1133-1139
Number of pages7
JournalJournal of Electronic Materials
Volume39
Issue number8
Publication statusPublished - 1 Aug 2010
MoE publication typeA1 Journal article-refereed

    Research areas

  • Electrical and thermal conduction in crystalline metals and alloys, Scattering mechanisms and Kondo effect, Thermoelectric materials, Transition-metal compounds

ID: 35233568