Abstract The vibron quasi-bound state stability was analyzed for the series of compounds CeCuxAg1-xAl3, 0.2 γ , slightly increases with volume from 200 mJ/mol-K2 (x=0.85) to 210 mJ/mol-K2 (x=0.3), indicating small changes in the density of electronic states at Fermi level. The measurements of inelastic neutron scattering indicate the existence of underlaying two crystal field excitations for cerium ions in paramagnetic regime well described according with Vegard’s law while the volume of the series CeCuxAg1-xAl3 compounds is increased. Additionally, a new magnetic excitation is found only for CeCu0.85Ag0.15Al3 and CeCu0.7Ag0.3Al3 compounds that comes from the coupling between a crystal field excitation and a single “orthorhombic” phonon mode, via single ion magnetoelastic interaction. The intensity of this coupling increases from 0.4 meV/ion for CeCuAl3 to 0.7 meV/ion for CeCu0.7Ag0.3Al3, but after, it fades away for CeCu0.3Ag0.7Al3. The intensity of this coupling is highly dependent on the energy resonance between phonon mode and crystal field excitation, but also on the strength of the oscillator that vanishes when the volume of the unit cell increases sufficiently. Furthermore, the existence of this coupling also suggests the presence of an effective attraction between pairs of 4 f - electrons that would explain the reduction of ordering temperatures for compounds with copper composition around to 0.5.

中文翻译：

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四方 CeCuxAg1-xAl3 的 Vibron 准束缚态稳定性

摘要 分析了CeCuxAg1-xAl3, 0.2 γ , 随着体积从200 mJ/mol-K2 (x=0.85) 到210 mJ/mol-K2 (x=0.3) 的系列化合物的振子准结合态稳定性，表明费米能级电子态密度的微小变化。非弹性中子散射的测量表明，在按照 Vegard 定律很好地描述的顺磁区中，存在两个用于铈离子的底层晶体场激发，而系列 CeCuxAg1-xAl3 化合物的体积增加。此外，仅针对 CeCu0.85Ag0.15Al3 和 CeCu0.7Ag0.3Al3 化合物发现了一种新的磁激发，它来自晶体场激发和单个“正交”声子模式之间的耦合，通过单离子磁弹性相互作用。这种耦合的强度从 0 增加。CeCuAl3 为 4 meV/ion，CeCu0.7Ag0.3Al3 为 0.7 meV/ion，但之后，CeCu0.3Ag0.7Al3 逐渐消失。这种耦合的强度高度依赖于声子模式和晶体场激发之间的能量共振，而且还依赖于当晶胞体积充分增加时振荡器消失的强度。此外，这种耦合的存在也表明 4 f - 电子对之间存在有效吸引力，这可以解释铜成分的化合物的排序温度降低到 0.5 左右。但也取决于当晶胞的体积充分增加时振荡器消失的强度。此外，这种耦合的存在也表明 4 f - 电子对之间存在有效吸引力，这可以解释铜成分约为 0.5 的化合物的排序温度降低。但也取决于当晶胞的体积充分增加时振荡器消失的强度。此外，这种耦合的存在也表明 4 f - 电子对之间存在有效吸引力，这可以解释铜成分的化合物的排序温度降低到 0.5 左右。