Hu Shichao, Johnsson Mats, Law Joseph M, Bettis Jerry L, Whangbo Myung-Hwan, Kremer Reinhard K
Department of Materials and Environmental Chemistry, Stockholm University , SE-106 91 Stockholm, Sweden.
Inorg Chem. 2014 Apr 21;53(8):4250-6. doi: 10.1021/ic5003995. Epub 2014 Mar 31.
The new oxofluoride FeSeO3F, which is isostructural with FeTeO3F and GaTeO3F, was prepared by hydrothermal synthesis, and its structure was determined by X-ray diffraction. The magnetic properties of FeSeO3F were characterized by magnetic susceptibility and specific heat measurements, by evaluating its spin exchanges on the basis of density functional theory (DFT) calculations, and by performing a quantum Monte Carlo simulation of the magnetic susceptibility. FeSeO3F crystallizes in the monoclinic space group P21/n and has one unique Se(4+) ion and one unique Fe(3+) ion. The building blocks of FeSeO3F are [SeO3] trigonal pyramids and cis-[FeO4F2] distorted octahedra. The cis-[FeO4F2] octahedra are condensed by sharing the O-O and F-F edges alternatingly to form [FeO3F]∞ chains, which are interconnected via the [SeO3] pyramids by corner-sharing. The magnetic susceptibility of FeSeO3F is characterized by a broad maximum at 75(2) K and a long-range antiferromagnetic order below ∼45 K. The latter is observed by magnetic susceptibility and specific heat measurements. DFT calculations show that the Fe-F-Fe spin exchange is stronger than the Fe-O-Fe exchange, so each [FeO3F]∞ chain is a Heisenberg antiferromagnetic chain with alternating antiferromagnetic spin exchanges. The temperature dependence of the magnetic susceptibility is well-reproduced by a quantum-Monte Carlo simulation.
新型氧氟化物FeSeO3F与FeTeO3F和GaTeO3F同构，通过水热合成法制备，并通过X射线衍射确定其结构。通过磁化率和比热测量、基于密度泛函理论（DFT）计算评估其自旋交换以及对磁化率进行量子蒙特卡罗模拟，对FeSeO3F的磁性进行了表征。FeSeO3F结晶于单斜空间群P21/n，有一个独特的Se(4+)离子和一个独特的Fe(3+)离子。FeSeO3F的结构单元是[SeO3]三角锥和顺式-[FeO4F2]畸变八面体。顺式-[FeO4F2]八面体通过交替共享O - O和F - F边而缩合形成[FeO3F]∞链，这些链通过[SeO3]三角锥以角共享的方式相互连接。FeSeO3F的磁化率特征是在75(2) K处有一个宽峰，在约45 K以下存在长程反铁磁序。后者通过磁化率和比热测量观察到。DFT计算表明，Fe - F - Fe自旋交换比Fe - O - Fe交换更强，因此每个[FeO3F]∞链是一个具有交替反铁磁自旋交换的海森堡反铁磁链。量子蒙特卡罗模拟很好地再现了磁化率的温度依赖性。
