放电等离子烧结
材料科学
磁电阻
热电效应
化学计量学
电阻率和电导率
陶瓷
晶界
铁磁性
三角晶系
凝聚态物理
塞贝克系数
热导率
分析化学(期刊)
热电材料
矿物学
冶金
复合材料
结晶学
晶体结构
化学
热力学
磁场
微观结构
物理化学
电气工程
色谱法
工程类
物理
量子力学
作者
A. Maignan,Yohann Bréard,Emmanuel Guilmeau,Franck Gascoin
摘要
By using the spark plasma sintering technique, a dense Cr2S3−x ceramic, crystallizing in the trigonal P3¯1c space group of Cr2S3, has been prepared by starting from a powder of R3¯ Cr2S3 precursor. The Cr and S contents of the densified sample deviate from the 2/3 ratio, indicating the presence of extra Cr at the level of the deficient “Cr1/3S” layer of the Cr2S3 structure, thus leading to the Cr2S2.8 formula. In contrast to the large magnetoresistance associated to the ferromagnetic-like component in the stoichiometric rhombohedral precursor, no significant negative magnetoresistance could be measured in the trigonal, sulfur deficient, Cr2S3. However, the non stoichiometry and the densification induce a higher charge carrier concentration and a reduced contribution of the grain boundaries, respectively. This explains the low resistivity value, ρ300 K = 2.65 mΩ · cm. With the thermal conductivity remaining below 2 W · m−1K−1 up to 700 K, a thermoelectric figure of merit reaching zT = 0.12 at 675 K is achieved.
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