Magnetocaloric effect, thermal conductivity, and magnetostriction of epoxy-bonded La(Fe0.88Si0.12) 13 hydrides
Magnetocaloric effect, thermal conductivity, and magnetostriction of epoxy-bonded La(Fe0.88Si0.12) 13 hydrides
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环氧树脂La(Fe0.88Si0.12) 13 氢化物的磁热效应、热导率和磁致伸缩
DOI：
10.1088/1742-6596/897/1/012011
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Y Matsumoto and T Kuriiwa
中科院分区：
文献类型：
--
作者：
K Matsumoto;D Murayama;M Takeshita;Y Ura;S Abe;T Numazawa;H Takata;Y Matsumoto and T Kuriiwa
具有大磁热效应的磁性材料对于磁制冷具有重要意义。 La(Fe 0.88 Si 0.12) 13 化合物是具有一级磁相变的有前途的磁热材料之一。氢化La(Fe 0.88 Si 0.12) 13 的转变温度升高至室温范围，同时保持变磁转变特性。从实际应用的角度来看，粘合复合材料非常有吸引力，其性能也很重要。我们制备了环氧键合的La(Fe 0.88 Si 0.12) 13 氢化物。通过测量绝热退磁中的比热、磁化强度和温度变化来研究磁热效应。该复合材料在2T中的熵变比氢化La(Fe 0.88 Si 0.12) 13粉末小约20%。复合材料的热导率比La(Fe, Si) 13小数倍。热导率较小的原因是环氧树脂的热导率较小。观察到热导率对 2 T 磁场不敏感。测量了复合材料的热膨胀和磁致伸缩。当复合材料进入铁磁相时，膨胀约0.25%。铁磁相复合材料的磁致伸缩在5T下约为0.2%，远大于顺磁相。尽管该复合材料具有磁致伸缩特性，但在绝热退磁实验中，经过约100次磁场变化后，该复合材料并未破裂。
Magnetic materials with large magnetocaloric effect are significantly important for magnetic refrigeration. La (Fe 0.88 Si 0.12) 13 compounds are one of the promising magnetocaloric materials that have a first order magnetic phase transition. Transition temperature of hydrogenated La (Fe 0.88 Si 0.12) 13 increased up to room temperature region while keeping metamagnetic transition properties. From view point of practical usage, bonded composite are very attractive and their properties are important. We made epoxy bonded La (Fe 0.88 Si 0.12) 13 hydrides. Magnetocaloric effect was studied by measuring specific heat, magnetization, and temperature change in adiabatic demagnetization. The composite had about 20% smaller entropy change from the hydrogenated La (Fe 0.88 Si 0.12) 13 powder in 2 T. Thermal conductivity of the composite was several times smaller than La (Fe, Si) 13. The small thermal conductivity was explained due to the small thermal conductivity of epoxy. Thermal conductivity was observed to be insensitive to magnetic field in 2 T. Thermal expansion and magnetostriction of the composite material were measured. The composite expanded about 0.25% when it entered into ferromagnetic phase. Magnetostriction of the composite in ferromagnetic phase was about 0.2% in 5 T and much larger than that in paramagnetic phase. The composite didn't break after about 100 times magnetic field changes in adiabatic demagnetization experiment even though it has magnetostriction.