Unexpected Hydride: Ce 4 B 2 C 2 H 2.42 , a Stuffed Variant of the Nd 2 BC Structure Type
Unexpected Hydride: Ce 4 B 2 C 2 H 2.42 , a Stuffed Variant of the Nd 2 BC Structure Type
复制标题
意外氢化物：Ce 4 B 2 C 2 H 2.42，Nd 2 BC 结构类型的填充变体
DOI：
10.1021/acs.cgd.1c00521
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发表时间：
2021
影响因子：
3.8
通讯作者：
Latturner, Susan E.
中科院分区：
文献类型：
--
作者：
Hertz, Mary B.;Baumbach, Ryan;Wang, Xiaoping;Latturner, Susan E.
采用Ce/Cu共晶助熔剂生长了Ce_4B_2C_2H_2.42大晶体。单晶X射线和中子衍射的结构，其特征在于，被发现是一个填充的变种Nd 2BC与另外两个间隙氢的位置。四面体氢位置被完全占据，而八面体位置具有42（3）%的占据率。最初的合成是由于氢污染的铈金属，但已成功地重复使用蒽作为碳和氢源。态密度的计算表明，氢的掺入稳定的化合物相对于nonbridded模型。磁化率数据显示，在7.7 K下存在复杂的磁有序，其起源于结构中Ce 3+上的局域电子。三价态也支持X射线光电子能谱测量。热容和电阻率数据表明，相变是宽的温度，这可能是由于结构无序。C/T的大低温值也表明可能的重费米子行为。
Ce4B2C2H2.42was grown as large crystals from a cerium/copper eutectic flux. The structure was characterized by single-crystal X-ray and neutron diffraction and was found to be a stuffed variant of Nd2BC with the addition of two interstitial hydrogen positions. The tetrahedral hydrogen position is fully occupied, while the octahedral position has an occupancy of 42(3)%. Initial synthesis was due to hydrogen contamination of the cerium metal but has been successfully repeated using anthracene as a carbon and hydrogen source. Density of states calculations suggest that the incorporation of hydrogen stabilizes the compound with respect to the nonhydrided model. Magnetic susceptibility data show a complex magnetic ordering at 7.7 K that originates from the localized electron on the Ce3+in the structure. The trivalent state is also supported by X-ray photoelectron spectroscopy measurements. Heat capacity and electrical resistivity data show that the phase transition is broad in temperature, which may be due to structural disorder. The large low temperature value ofC/Talso indicates possible heavy fermion behavior.