New Regenerator Material for Sub-4 K Cryocoolers
New Regenerator Material for Sub-4 K Cryocoolers
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用于低于 4 K 低温冷却器的新型蓄热材料
DOI：
10.1007/0-306-47112-4_59
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
T. Yanagitani
中科院分区：
文献类型：
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作者：
T. Numazawa;O. Arai;A. Sato;S. Fujimoto;T. Oodo;Y. Rang;T. Yanagitani
研究了一种用于亚4 K低温制冷机的新型磁蓄冷材料。一些稀土氧化物磁性材料具有提供低于4K的高热容的潜力。通过对石榴石和钙钛矿型稀土氧化物的研究，我们发现钙钛矿型GdAlO 3（GAP）在4K以下具有非常大的体积热容，可以用作蓄冷材料。用化学方法制备了尺寸在100 ~ 500 μm之间的多晶GAP微粒。所制备的GAP的热容与单晶材料的热容具有良好的一致性，并且当施加1 T的磁场时，磁场依赖性可以忽略。从热导率测量，GAP被发现有3 - 10倍高于SUS的热导率从5 K到20 K。制冷试验也是在一台4K脉管制冷机上进行的，该制冷机配有一台3.3kW的压缩机。当在第二级回热器的低温部分使用GAP时，在4.2K下的冷却功率从165 mW显著增加到250 mW。最低空载温度从2.9K降低到2.5K。GAP的体积比存在一个最佳值，对应于最佳的冷却性能。
A new magnetic regenerator material for sub-4 K cryocoolers has been studied. Some rare-earth oxide magnetic materials have the potential to provide a high heat capacity below 4 K. From surveying the garnets and perovskites rare-earth oxides, we have found that a perovskite GdAlO3(GAP) has a very large volumetric heat capacity below 4 K and it is useful as a regenerator material. Fine particles of the polycrystal GAP between 100 and 500 μm sizes were fabricated by a chemical process. The measured heat capacity of the fabricated GAP was in good agreement with that of single crystal material, and the magnetic field dependence was negligible when applying a magnetic field of 1 T. From thermal conductivity measurements, GAP was found to have 3 ∼10 times higher thermal conductivity than that of SUS from 5 K to 20 K. A refrigeration test was also done with a 4 K pulse tube refrigerator operating with a 3.3 kW compressor. The cooling power was increased remarkably from 165 mW to 250 mW at 4.2 K when using GAP in the lower temperature portion of the 2nd-stage regenerator. The minimum no-load temperature was lowered from 2.9 K to 2.5 K. There was an optimum value for the volumetric ratio of GAP that corresponded to the best cooling performance.