Rapid Microwave Preparation and Composition Tuning of the High-Performance Magnetocalorics (Mn,Fe) 2 (P,Si)
Rapid Microwave Preparation and Composition Tuning of the High-Performance Magnetocalorics (Mn,Fe) 2 (P,Si)
复制标题
高性能磁热材料 (Mn,Fe) 2 (P,Si) 的快速微波制备和成分调节
DOI：
10.1021/acsami.7b16988
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发表时间：
2018
影响因子：
9.5
通讯作者：
Wilson, Stephen D.
中科院分区：
文献类型：
--
作者：
Grebenkemper, Jason H.;Bocarsly, Joshua D.;Levin, Emily E.;Seward, Gareth;Heikes, Colin;Brown, Craig;Misra, Sumohan;Seeler, Fabian;Schierle-Arndt, Kerstin;Wilson, Stephen D.
利用辅助微波加热的快速制备允许显著缩短（Mn，Fe）2（P，Si）族磁热化合物的制备时间，特别是起始组成为δ = 0、0.06和0.12的（Mn，Fe）2-δ P0.5Si0.5样品。为了充分了解加工和成分变化对结构和性能的影响，这些材料的特征在于使用同步加速器粉末衍射，中子粉末衍射，电子探针分析（EMPA），X射线荧光（XRF）和磁性测量。衍射分析表明，δ的增加导致了普通Heusler（Mn，Fe）3Si第二相的减少。EMPA显示所有三个样品中的（Mn，Fe）2（P，Si）富含Mn和P，而XRF表明本体材料富含Mn但缺乏P。增加δ使Mn/Fe和P/Si比更接近其起始值。磁性测量表明，随着δ的增加，饱和磁化强度和有序温度增加，与Fe和Si含量的增加一致。增加δ也会导致热滞后的降低和磁熵变的增加，后者达到的值接近之前报道的需要更长时间制备的样品。
Rapid preparation utilizing assisted microwave heating permits significantly shorter preparation times for magnetocaloric compounds in the (Mn,Fe)2(P,Si) family, specifically samples of (Mn,Fe)2−δP0.5Si0.5with starting compositions of δ = 0, 0.06, and 0.12. To fully understand the effects of processing and composition changes on structure and properties, these materials are characterized using synchrotron powder diffraction, neutron powder diffraction, electron microprobe analysis (EMPA), X-ray fluorescence (XRF), and magnetic measurements. The diffraction analysis reveals that increasing δ results in decreasing amounts of the common Heusler (Mn,Fe)3Si secondary phase. EMPA shows (Mn,Fe)2(P,Si) in all three samples to be Mn and P rich, whereas XRF demonstrates that the bulk material is Mn rich yet P deficient. Increasing δ brings the Mn/Fe and P/Si ratios closer to their starting values. Measurements of magnetic properties show an increase in saturation magnetization and ordering temperature with increasing δ, consistent with the increase in Fe and Si contents. Increasing δ also results in a decrease in thermal hysteresis and an increase in magnetic entropy change, the latter reaching values close to what have been previously reported on samples that take much longer to prepare.