Magnetic coupling between nonmagnetic ions:: Eu3+ in EuN and EuP -: art. no. 195116
Magnetic coupling between nonmagnetic ions:: Eu3+ in EuN and EuP -: art. no. 195116
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DOI：
10.1103/physrevb.72.195116
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发表时间：
2005-11-01
影响因子：
3.7
通讯作者：
Pickett, WE
中科院分区：
文献类型：
--
作者：
Johannes, MD;Pickett, WE
我们考虑了岩盐结构化合物EuN和EuP的电子结构和名义上的Eu ~（3+）离子（4f（6），S=3，L=3，J=0）之间的磁交换（自旋）相互作用。这两种化合物都是类似于等价GdN的离子（Eu 3 +; N3-和P3-）半金属。在4f壳层内处理自旋极化，然后平均与J=0配置一致，我们估计半金属带重叠（Eu 5d与磷属元素化物2 p或3 p）类似于0.1 eV（EuN）和类似于1.0 eV（EuP），随着压力的增加（变得更金属化）。EuN（EuP）的体积弹性模量为130（86）GPa。交换（自旋-自旋）耦合计算相关能带理论是小的和铁磁的符号为EuN，增加的幅度与压力。相反，交换耦合是反铁磁符号EuP和更大的幅度，但随着压缩。研究了在J= 0，1空间内具有S-1中心点S-2耦合的双位模型，说明了磁关联函数对模型参数的依赖性，并指出自旋耦合足以改变货车Vleck磁化率.我们概述了一个自旋相关跃迁的情况下，在晶格中的S=3，L=3，J=0的离子。
We consider the electronic structure of, and magnetic exchange (spin) interactions between, nominally nonmagnetic Eu3+ ions (4f(6), S=3, L=3, J=0) within the context of the rocksalt structure compounds EuN and EuP. Both compounds are ionic (Eu3+; N3- and P3-) semimetals similar to isovalent GdN. Treating the spin polarization within the 4f shell, and then averaging consistent with the J=0 configuration, we estimate semimetallic band overlaps (Eu 5d with pnictide 2p or 3p) of similar to 0.1 eV (EuN) and similar to 1.0 eV (EuP) that increase (become more metallic) with pressure. The calculated bulk modulus is 130 (86) GPa for EuN (EuP). Exchange (spin-spin) coupling calculated from correlated band theory is small and ferromagnetic in sign for EuN, increasing in magnitude with pressure. Conversely, the exchange coupling is antiferromagnetic in sign for EuP and is larger in magnitude, but decreases with compression. Study of a two-site model with S-1 center dot S-2 coupling within the J=0,1 spaces of each ion illustrates the dependence of the magnetic correlation functions on the model parameters, and indicates that the spin coupling is sufficient to alter the Van Vleck susceptibility. We outline a scenario of a spin-correlation transition in a lattice of S=3, L=3, J=0 nonmagnetic ions.