Magnetic Exchange in Oxides
Magnetic Exchange in Oxides
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DOI：
10.1007/978-1-4419-0054-8_3
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发表时间：
2009-01-01
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影响因子：
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通讯作者：
Dionne, Gerald F.
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文献类型：
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作者：
Dionne, Gerald F.
在上一章中，我们用基本晶场和分子轨道理论介绍了阴离子电荷对阳离子轨道角动量的猝灭和共价键稳定能量的起源。在磁性稀薄的化合物中，孤立的3dnions接下来受到自旋-轨道耦合作用减弱的微扰和多重态结构的影响，这些结构决定了将要在第一章中研究的磁弹性性质。5.这些效应最初是局部的，但当浓度增加到可能发生渗流的水平时，这些效应可以变得协同，例如，协同的Jahn-Teller效应。然而，由于自旋本身就是这个系列中磁性有序的作用者，所以在讨论自发磁性时，可以很大程度上忽略多重态的能量。因此，配位体晶格中下一个需要解决的重要有效场是由连接磁性阳离子的转移积分引起的磁场交换场。因此，磁交换是用来描述离子晶格中共价耦合的原子或离子的自旋有序(平行或反平行)所获得的能量稳定的术语。
In the previous chapter, quenching of cation orbital angular momentum by the anion charges and the origin of the energy stabilization by covalent bonding was introduced by elementary crystal field and molecular orbital theory. In magnetically dilute compounds, the isolated 3dnions are influenced next by the weakened spin-orbit coupling perturbations and multiplet structures that determine the magnetoelastic properties to be examined in Chap. 5 . These effects are initially local but can become cooperative when concentrations increase to levels where percolation can occur, e.g., a cooperative Jahn-Teller effect. However, because the spin alone is the agent of magnetic ordering in this series, the multiplet energies can be largely ignored in the discussion of spontaneous magnetism. Consequently, the next important effective field in a ligand lattice to be addressed is the magnetic exchange field that arises from the transfer integral linking magnetic cations. Magnetic exchange, therefore, is the term used to describe the energy stabilization gained from spin ordering (parallel or antiparallel) of atoms or ions covalently coupled in an ionic crystal lattice.