Liu Wang, Liang Fei, Chen Yuwei, Song Huimin, Feng Jingcheng, Shen Jun, Lin Zheshuai, Tu Heng, Zhang Guochun
Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China.
Inorg Chem. 2021 May 3;60(9):6796-6803. doi: 10.1021/acs.inorgchem.1c00633. Epub 2021 Apr 12.
A new Gd-based borate crystal, LiKGd(BO), has been successfully obtained via the high-temperature solution method using LiO-KO-BO self-flux. It crystallizes in monoclinic space group 2/ (no. 10) with lattice parameters = 11.3454(6) Å, = 9.9881(4) Å, = 11.4467(7) Å, α = γ = 90 , β = 114.782(7) , and = 2. LiKGd(BO) exhibits an intriguing sandwich-like three-dimensional (3D) framework constructed from [Gd-B-O] layers, KO ( = 6 and 8) polyhedra, and LiO tetrahedra, in which [Gd-B-O] layers are built from two types of GdO polyhedra and triangular BO units. Magnetic measurements showed that LiKGd(BO) exhibits a large magnetocaloric effect with -Δ = 39.3 J kg K at 2.0 K for Δ = 7 T, which is slightly higher than that of the commercial gadolinium gallium garnet under the same conditions. The powder X-ray diffraction, infrared spectrum, and UV-vis-NIR diffuse reflectance spectrum were also performed to characterize LiKGd(BO). The electronic band structures, partial density of states, and refractive indices of LiKGd(BO) were investigated via the first-principle calculations.
一种新型的基于钆的硼酸盐晶体LiKGd(BO)，通过使用LiO-KO-BO自熔剂的高温溶液法成功获得。它结晶于单斜空间群2/（编号10），晶格参数为 = 11.3454(6) Å， = 9.9881(4) Å， = 11.4467(7) Å，α = γ = 90°，β = 114.782(7)°，且 = 2。LiKGd(BO)展现出一种由[Gd-B-O]层、KO（ = 6和8）多面体以及LiO四面体构成的有趣的三明治状三维（3D）框架，其中[Gd-B-O]层由两种类型的GdO多面体和三角形BO单元构建而成。磁性测量表明，LiKGd(BO)在2.0 K时对于Δ = 7 T展现出较大的磁热效应，-Δ = 39.3 J kg K，这在相同条件下略高于商业钆镓石榴石。还进行了粉末X射线衍射、红外光谱以及紫外-可见-近红外漫反射光谱以对LiKGd(BO)进行表征。通过第一性原理计算研究了LiKGd(BO)的电子能带结构、态密度以及折射率。
