两种新型层状化合物EuFAgSe和EuFAgTe的合成、电子结构及物理性质，其具有活性氧化还原对Eu/Ag。
Synthesis, electronic structure and physical properties of two new layered compounds, EuFAgSe and EuFAgTe, featuring the active redox pair Eu/Ag.
作者信息
Plokhikh Igor V, Tsirlin Alexander A, Heletta Lukas, Klenner Steffen, Charkin Dmitri O, Kuznetsov Alexey N, Shevelkov Andrei V, Pöttgen Rainer, Pfitzner Arno
机构信息
Univeristy of Regensburg, 93053 Regensburg, Germany.
Experimental Physics VI, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, 86135 Augsburg, Germany.
出版信息
Dalton Trans. 2020 Jun 9;49(22):7426-7435. doi: 10.1039/d0dt01504k.
Systematic studies of the ZrCuSiAs (also LaOAgS or 1111) structure type resulted in the synthesis of two new fluoride chalcogenides, EuFAgSe and EuFAg1-δTe, whereas their sulfide analog, EuFAgS, could not be obtained. Both new compounds are tetragonal, P4/nmm, with cell parameters a = 4.1542(1) Å, c = 9.2182(1) Å for the selenide and a = 4.3255(1) Å, c = 9.5486(1) Å for the telluride. Rietveld refinement reveals a significant silver deficiency in the telluride (δ = 0.05), while the selenide is nearly stoichiometric. Both compounds are semiconductors as shown by diffuse reflectance spectroscopy and confirmed by density-functional calculations of the band structure. Magnetism of both compounds is predominantly driven by Eu2+, as indicated by magnetic susceptibility measurements and corroborated by 151Eu Mössbauer spectroscopy. EuFAg1-δTe and EuFAgSe are paramagnetic down to 1.8 K.
对ZrCuSiAs（也称为LaOAgS或1111）结构类型的系统研究导致合成了两种新型氟化物硫属化物，EuFAgSe和EuFAg1-δTe，而它们的硫化物类似物EuFAgS无法获得。这两种新化合物均为四方晶系，P4/nmm，硒化物的晶胞参数为a = 4.1542(1) Å，c = 9.2182(1) Å，碲化物的晶胞参数为a = 4.3255(1) Å，c = 9.5486(1) Å。Rietveld精修显示碲化物中存在明显的银缺陷（δ = 0.05），而硒化物几乎是化学计量的。如漫反射光谱所示且经能带结构的密度泛函计算证实，这两种化合物均为半导体。磁化率测量表明这两种化合物的磁性主要由Eu2+驱动，151Eu穆斯堡尔光谱也证实了这一点。EuFAg1-δTe和EuFAgSe在温度低至1.8 K时均为顺磁性。
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