Quadrupolar ordering in CeAg
Quadrupolar ordering in CeAg
复制标题
CeAg 中的四极排序
DOI：
10.1016/0304-8853(88)90080-7
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发表时间：
1988
影响因子：
2.7
通讯作者：
P. Morin
中科院分区：
文献类型：
--
作者：
P. Morin
在立方金属间化合物CeAg中，有几种不同的耦合假设：电子源晶格不稳定性、双线性铁磁相互作用、近藤型耦合以及四极相互作用。本文介绍了稀土-银等原子化合物的晶格性质，特别是关于三种立方弹性模态在整个系列中的变化。然后在CeAg的高温阶段确定四极相互作用的强度。四极相互作用在双线性相互作用中占主导地位，并在约10 K时驱动铁四极有序。事实上，这种跃迁是由晶格不稳定性引起的非调和弹性效应引起的，达到了实验值15.85 K。观察到四极和铁磁相的磁化过程强烈依赖于样品的应变域结构，并且由于四极相互作用而具有很强的各向异性。虽然计算出的磁自发矩比观测到的略大（1.67μ b，而不是1.25μB），但计算中描述了它们的平均特征。这种差异可能归因于能带极化，特别是在稀土-银等原子化合物中，以及近藤型效应。
Several different coupling have been assumed in the past to meet in the cubic intermetallic compound CeAg: lattice instability of electronic origin, bilinear ferromagnetic interaction, Kondo-type coupling as well as quadrupole interactions. A review of lattice properties in the rare-earth-silver equiatomic compounds is presented here, in particular relating to the variation of the three cubic elastic modes across the series. The strength of the quadrupole interactions is then determined in the high-temperature phase of CeAg. Quadrupole interactions have been found to dominate bilinear ones and to drive a ferroquadrupolar ordering at about 10 K. In fact, this transition is shifted up to the experimental value of 15.85 K by anharmonic elasticity effects induced by the underlying lattice instability. Magnetization processes in the quadrupole and ferromagnetic phases are observed to be strongly dependent on the strain domain structure of the sample and to be very anisotropic due to quadrupole interactions. Calculations describe them in their mean features although the magnetic spontaneous moment is calculated a little larger than is observed (1.67μBinstead of 1.25μB). This difference may be attributed to the band polarization, particularly large in rare-earth-silver equiatomic compounds, as well as to a Kondo-type effect.