Optimization of the Magnetocaloric Effect in Low Applied Magnetic Fields in LnOHCO3 Frameworks
Optimization of the Magnetocaloric Effect in Low Applied Magnetic Fields in LnOHCO3 Frameworks
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DOI：
10.1021/acs.inorgchem.8b01549
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发表时间：
2018-10-15
影响因子：
4.6
通讯作者：
Saines, Paul J.
中科院分区：
文献类型：
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作者：
Dixey, Richard J. C.;Saines, Paul J.
本研究探讨了LnOHCO(3) （Ln = Gd3+, Tb3+, Dy3+， Ho3+和Er3+）框架的结构和磁热效应。单晶x射线和中子粉末衍射相结合表明，在这些合成条件下，这些材料完全采用P2(1)2(1)2(1)结构，磁化率测量表明，它们在2 K以下仍保持顺磁性。结果表明，在2 ~ 0 T的磁场变化下，TbOHCO3和DyOHCO3的磁热效应峰值熵变化分别为30.99和33.34 J K-1，高于中等磁场下4 K以上的GdOHCO3框架。TbOHCO3和DyOHCO3在4 K以上磁场变化小于2 T时的磁熵变化也超过了Gd3Ga5O12和Dy3Ga5O12，使它们成为在液氦温度下使用的合适的磁冷却材料，使用永磁体可以获得的低磁场，有利于高效的实用冷却装置。
This study probes the structure and magneto caloric effect of the LnOHCO(3) (Ln = Gd3+, Tb3+, Dy3+, Ho3+, and Er3+) frameworks. The combination of single crystal X-ray and neutron powder diffraction indicates that these materials solely adopt the P2(1)2(1)2(1) structure under these synthetic conditions and magnetic susceptibility measurements indicate they remain paramagnetic down to 2 K. We show that the magnetocaloric effects of TbOHCO3 and DyOHCO3 have peak entropy changes of 30.99 and 33.34 J K-1 for a 2-0 T field change, respectively, which are higher than that of the promising GdOHCO3 framework above 4 K in moderate magnetic fields. The magnetic entropy changes of TbOHCO3 and DyOHCO3 above 4 K for smaller than 2 T field changes also exceed those of Gd3Ga5O12 and Dy3Ga5O12, making them suitable magnetic cooling materials for use at liquid helium temperatures using the low applied magnetic fields accessible using permanent magnets, advantageous for efficient practical cooling devices.