On the Structural and Electronic Factors Governing the Magnetic Properties of the Hexagonal Perovskite-Type Oxides AxBO3 (A=Ca, Sr, Ba; B=Co, Ni)
On the Structural and Electronic Factors Governing the Magnetic Properties of the Hexagonal Perovskite-Type Oxides AxBO3 (A=Ca, Sr, Ba; B=Co, Ni)
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影响六方钙钛矿型氧化物 AxBO3 (A=Ca, Sr, Ba; B=Co, Ni) 磁性能的结构和电子因素
DOI：
10.1006/jssc.2001.9230
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发表时间：
2001
影响因子：
5.4
通讯作者：
R. Brec
中科院分区：
文献类型：
--
作者：
M. Whangbo;H. Koo;K.;O. Gourdon;M. Evain;S. Jobic;R. Brec
摘要六方钙钛矿型氧化物A × bo3 （A =Ca, Sr, Ba; B =Co, Ni）由bo6八面体和bo6三棱柱组成的(bo3)∞链组成。在分子轨道计算的基础上，我们研究了为什么Sr 9/7 NiO 3和Sr 14/11 CoO 3的三棱柱中的过渡金属原子占据了远离三棱柱中心的位置，以及为什么Ba 6/5 NiO 3和Ca 3/2 CoO 3表现出明显令人困惑的磁性。我们的分析表明，这些氧化物中的(b_3)∞链的结构构建单元采用高自旋态来减少相邻金属原子之间的金属-金属σ-反键相互作用以及现场排斥。这一发现使我们预测了氧化物Sr 9/7 NiO 3、Sr 6/5 CoO 3和Sr 14/11 CoO 3的不成对自旋数。
Abstract The hexagonal perovskite-type oxides A x B O 3 ( A =Ca, Sr, Ba; B =Co, Ni) consist of ( B O 3 ) ∞ chains made up of face-sharing B O 6 octahedra and B O 6 trigonal prisms. On the basis of molecular orbital calculations for their structural building blocks we examined why the transition metal atoms in the trigonal prisms of Sr 9/7 NiO 3 and Sr 14/11 CoO 3 occupy the positions away from their trigonal prism centers and why Ba 6/5 NiO 3 and Ca 3/2 CoO 3 exhibit apparently puzzling magnetic properties. Our analysis indicates that the structural building units of the ( B O 3 ) ∞ chains in these oxides adopt high-spin states to reduce the metal–metal σ-antibonding interactions between adjacent metal atoms as well as the on-site repulsion. This finding led us to predict the number of unpaired spins that the oxides Sr 9/7 NiO 3 , Sr 6/5 CoO 3 , and Sr 14/11 CoO 3 are expected to have.