Resistivity, thermopower, and thermal conductivity of nickel doped compounds Cr1−xNixSb2 at low temperatures

• Published in: Journal of alloys and compounds Vol. 509; no. 8; pp. 3677 - 3681
• Main Authors: Li, Hai Jin, Qin, Xiao Ying, Liu, Yi, Li, Di, Hu, Jin Lian
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 24.02.2011; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Conductivity of specific materials; Cr1−xNixSb2; Electrical resistivity; Electronic transport in condensed matter; Exact sciences and technology; Iii-v and ii-vi semiconductors; Physics; Thermal conductivity; Thermopower; Thermal conductivity; Thermopower; Electrical resistivity; Cr1−xNixSb2; Temperature dependence; Electrical conductivity; Transport properties; Phonon-phonon interactions; Doping; Nickel additions; Thermoelectric properties; Cr; Sb; Thermoelectric power; Electric resistivity; Nickel compounds; Transport processes; Ni; Phonon scattering; Carrier density; Figure of merit; Lattice thermal conductivity
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2010.12.159

▶ Thermoelectric properties of Cr1−xNixSb2 were improved due to the decrease in resistivity and thermal conductivity. ▶ The decrease in resistivity and thermopower of Cr1−xNixSb2 may be due to an increase in electron concentration due to Ni substitution for Cr. ▶ The decrease in thermal conductivity of Cr1−xNixSb2 with increasing Ti content could be due to an enhancement of phonon scattering by increased number of Ti atoms. ▶ The Neel temperature of Cr1−xNixSb2 decreased from 273K for CrSb2 to 195K for Cr0.9Ni0.1Sb2, which may be caused by the substitution of the low spin state Ni (3d6) for high spin state Cr (3d2), weakening the effective moment of doping compounds. Substitutional compounds Cr1−xNixSb2 (0≤x≤0.1) were synthesized, and the effect of Ni substitution on transport and thermoelectric properties of Cr1−xNixSb2 were investigated at the temperatures from 7 to 310K. The results indicated that the magnitudes of the resistivity and thermopower of Cr1−xNixSb2 decreased greatly with increasing Ni content at low temperatures, owing to an increase in electron concentration caused by Ni substitution for Cr. Experiments also showed that the low-temperature lattice thermal conductivity of Cr1−xNixSb2 decreased substantially with increasing Ni content due to an enhancement of phonon scattering by the increased number of Ni atoms. As a result, the figure of merit, ZT, of lightly doped Cr0.99Ni0.01Sb2 was improved at T>∼230K. Specifically, the ZT of Cr0.99Ni0.01Sb2 at 310K was approximately ∼29% larger than that of CrSb2, indicating that thermoelectric properties of CrSb2 can be improved by an appropriate substitution of Ni for Cr.