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Eu11Zn4Sn2As12: A Ferromagnetic Zintl Semiconductor with a Layered Structure Featuring Extended Zn4As6 Sheets and Ethane-like Sn2As6 Units
Chemistry of Materials ( IF 8.6 ) Pub Date : 2018-09-21 00:00:00 , DOI: 10.1021/acs.chemmater.8b02749
Kasey P. Devlin 1 , Nasrin Kazem 1 , Julia V. Zaikina 1 , Joya A. Cooley 1 , Jackson R. Badger 1 , James C. Fettinger 1 , Valentin Taufour 2 , Susan M. Kauzlarich 1
Affiliation  

We report the synthesis, structure, and magnetic properties of a new Zintl phase and structure type, Eu11Zn4Sn2As12. The structure and composition of this phase have been established by single-crystal X-ray diffraction and electron microprobe analysis. Eu11Zn4Sn2As12 crystallizes in monoclinic space group C2/c (No. 15) with the following lattice parameters: a = 7.5679(4) Å, b = 13.0883(6) Å, c = 31.305(2) Å, and β = 94.8444(7)° [R1 = 0.0398; wR2 = 0.0633 (all data)]. The anisotropic structural features staggered ethane-like [Sn2As6]12– units and infinite 2[Zn2As3]5– sheets extended in the a–b plane. Eu cations fill the space between these anionic motifs. Temperature-dependent magnetic properties and magnetoresistance of this Zintl phase have been studied, and the electronic structure and chemical bonding were elucidated using first-principles quantum chemical calculations (TB-LMTO-ASA). Quantum chemical calculations show that the ethane-like units can be considered as consisting of covalent single bonds; however, the 2[Zn2As3]5– sheets are best described with delocalized bonding and there is evidence of Eu–As interactions. Temperature-dependent magnetization and transport properties between 2 and 300 K show a ferromagnetic transition at 15 K, a band gap of 0.04 eV, and negative colossal magnetoresistance.

中文翻译:

Eu 11 Zn 4 Sn 2 As 12:具有扩展Zn 4 As 6片和乙烷状Sn 2 As 6单元的层状结构的铁磁Zintl半导体

我们报告了一种新的Zintl相和结构类型Eu 11 Zn 4 Sn 2 As 12的合成,结构和磁性能。通过单晶X射线衍射和电子探针分析已经确定了该相的结构和组成。Eu 11 Zn 4 Sn 2 As 12在单斜空间群C 2 / c(No. 15)中结晶,具有以下晶格参数:a = 7.5679(4)Å,b = 13.0883(6)Å,c = 31.305(2) ,β= 94.8444(7)°[ R 1 = 0.0398; R2 = 0.0633(所有数据)]。各向异性结构特征交错乙烷状[Sn的2作为6 ] 12-单元和无穷2 [的Zn 2作为3 ] 5-片延伸在A-B平面上。Eu阳离子填充了这些阴离子基序之间的空间。研究了该Zintl相的随温度变化的磁性能和磁阻,并使用第一性原理量子化学计算(TB-LMTO-ASA)阐明了电子结构和化学键合。量子化学计算表明,类似乙烷的单元可被视为由共价单键组成;但是,2 [Zn 2 As 3 ] 5–片最好用离域键进行描述,并且有Eu-As相互作用的证据。在2至300 K之间随温度变化的磁化和输运特性显示在15 K时发生铁磁跃迁,0.04 eV的带隙和负的巨大磁阻。
更新日期:2018-09-21
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