(Mn1-xFex)5Sn3合金晶体结构和居里温度

用粉末冶金法(磁场压制烧结)制备(Mn1-xFex)5Sn3(x=0.1～0.5)合金,对其晶体结构、居里温度进行研究。室温XRD分析表明,该系列合金均保持Mn5Sn3的InNi2型相结构,计算发现合金的晶格常数随着x量增大而减小。通过M-T曲线测量结果表明:居里温度TC在室温附近244～391K连续可调,且随着Fe含量的增加而提高,居里温度随成分近似呈线性变化;成分为(Mn0.70Fe0.30)5Sn3合金的居里温度为295K,在外加磁场为0～1.5T下,最大磁熵变约为0.87J·(kg·K)-1,是一种成本低廉的室温磁制冷候选材料。

Crystal Structure and Curie Temperature of (Mn1-xFex)5Sn3 Alloy

(Mn1-xFex)5Sn3 (x=0.1-0.5) alloys were prepared by powder metallurgy method with magnetic field pressing and sintering. The crystal structure, Curie temperature and magnetic entropy change of the alloys were studied. XRD patterns reveal that all samples of this system maintain a hexagonal InNi2-type structure with space group P63/mmc. The lattice parameter and cell volumes of the (Mn1-xFex)5Sn3 alloys decrease with x increasing by calculation, while the Curie temperature of these alloys increases almost linearly and is tunable continually from 244 K to 391 K by M-T curves. The Curie temperature of (Mn0.70Fe0.30)5Sn3 is about 295 K close to room temperature, and the maximum magnetic entropy change is 0.87 (kg·K)-1 with a field change from 0 to 1.5 T. The curve of magnetic entropy change of (Mn0.70Fe0.30)5Sn3 is flat in a wide temperature range. It is indicated that the (Mn1-xFex)5Sn3 alloy is a suitable candidate with low cost for Ericsson cycle.