Devlin Kasey P, Zhang Junjie, Fettinger James C, Choi Eun Sang, Hauble Ashlee K, Taufour Valentin, Hermann Raphael P, Kauzlarich Susan M
Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, United States.
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
Inorg Chem. 2021 Apr 19;60(8):5711-5723. doi: 10.1021/acs.inorgchem.0c03769. Epub 2021 Mar 30.
The structure, magnetic properties, and Eu and Sn Mössbauer spectra of the solid-solution EuSrZnSnAs are presented. A new commensurately modulated structure is described for EuZnSnAs (3 space group, average structure) that closely resembles the original structural description in the monoclinic 2/ space group with layers of Eu, puckered hexagonal ZnAs sheets, and ZnAs ethane-like isolated pillars. The solid-solution EuSrZnSnAs (0 < < 10) is found to crystallize in the commensurately modulated 3 space group, related to the parent phase but lacking the mirror symmetry. EuZnSnAs orders with a saturation plateau at 1 T for 7 of the 11 Eu cations ferromagnetically coupled (5 K) and shows colossal magnetoresistance at 15 K. The magnetic properties of EuZnSnAs are investigated at higher fields, and the ferromagnetic saturation of all 11 Eu cations occurs at ∼8 T. The temperature-dependent magnetic properties of the solid solution were investigated, and a nontrivial structure-magnetization correlation is revealed. The temperature-dependent Eu and Sn Mössbauer spectra confirm that the europium atoms in the structure are all Eu and that the tin is consistent with an oxidation state of less than four in the intermetallic region. The spectral areas of both Eu(II) and Sn increase at the magnetic transition, indicating a magnetoelastic effect upon magnetic ordering.
本文介绍了固溶体EuSrZnSnAs的结构、磁性以及Eu和Sn的穆斯堡尔谱。文中描述了EuZnSnAs（3空间群，平均结构）的一种新的同结构调制结构，它与单斜2/空间群中的原始结构描述非常相似，具有Eu层、褶皱的六方ZnAs片以及类似乙烷的孤立ZnAs柱。发现固溶体EuSrZnSnAs（0 << 10）在同结构调制的3空间群中结晶，与母相相关但缺乏镜面对称性。对于11个Eu阳离子中的7个铁磁耦合（5 K），EuZnSnAs在1 T时有序出现饱和平台，并在15 K时显示出巨大磁电阻。在更高磁场下研究了EuZnSnAs的磁性，所有11个Eu阳离子的铁磁饱和在约8 T时发生。研究了固溶体的温度依赖性磁性，并揭示了一种非平凡的结构 - 磁化相关性。温度依赖性Eu和Sn穆斯堡尔谱证实结构中的铕原子均为Eu，并且在金属间区域锡的氧化态小于四是一致的。在磁性转变时，Eu(II)和Sn的谱面积均增加，表明磁有序时存在磁弹性效应。
