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• 作者：Nicholas A. Moroz ; Juan S. Lopez ; Honore Djieutedjeu ; Kulugammana G. S. Ranmohotti ; Alan Olvera ; Pan Ren ; Alexander Page ; Nathan J. Takas ; Ctirad Uher ; Pierre F. P. Poudeu
• 刊名：Chemistry of Materials
• 出版年：2016
• 出版时间：December 13, 2016
• 年：2016
• 卷：28
• 期：23
• 页码：8570-8579
• 全文大小：592K
• ISSN：1520-5002

文摘

Single-phase samples of the solid-solution series FeSb_2–xIn_xSe₄ (0 ≤ x ≤ 0.25) were synthesized using solid-state reaction of the elements to probe the effect of electronic structure engineering on the magnetic behavior of the p-type semiconductor, FeSb₂Se₄. Powder X-ray diffraction data suggest that all samples are isostructural with FeSb₂Se₄. Rietveld refinements of the distribution of In atoms at various metal positions indicate a preferential substitution of Sb at the M1(4i) position within the magnetic layer A for In concentration up to x = 0.1. FeSb_2–xIn_xSe₄ compositions with higher In content show the distribution of In atoms at all metal positions, except for the M3(2d), which is fully occupied by Fe atoms. Interestingly, the ordering of Fe atoms within the crystal structure of FeSb_2–xIn_xSe₄ remains essentially unaffected by the degree of substitution (x values) and is comparable to the distribution of Fe atoms reported in FeSb₂Se₄. X-ray photoelectron spectroscopy confirms the oxidation states of various metal atoms In(+3), Sb(+3), Fe(+2) in the structure. Electronic transport properties indicate p-type semiconducting behavior for all samples. The electrical conductivity above 300 K first increases with In content, reaches the maximum value for x = 0.1, then decreases with further increase in In content. A reverse trend is observed for the thermopower. All samples show drastically low thermal conductivity with room temperature values ranging from 0.45 Wm^–1 K^–1 for x = 0 to 0.27 Wm^–1 K^–1 for the sample with x = 0.25. Magnetic susceptibility data suggest ferromagnetic-like behavior from 2–300 K for all samples. The magnitude of the magnetic susceptibility rapidly increases with In content, reaches a maximum for x = 0.1, and marginally decreases with further increase in In concentration. The observed surprising change in the magnetic and electronic behavior of samples with high In content (x > 0.1) is rationalized using the concept of antiferromagnetic scattering of charge carriers at the interfaces between overlapping bound magnetic polarons from adjacent layers A and B.