Ferroquadrupolar ordering in a magnetically ordered state in ErNiAl
Ferroquadrupolar ordering in a magnetically ordered state in ErNiAl
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ErNiAl 中磁有序状态的铁四极有序
DOI：
10.1103/physrevb.105.165147
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
and A. V. Andreev
中科院分区：
文献类型：
--
作者：
I. Ishii;Y. Kurata;Y. Wada;M. Nohara;T. Suzuki;K. Araki;and A. V. Andreev
我们进行了超声测量，以确定六方化合物ErNiAl在反铁磁相变温度K以下是否存在相变。我们发现横向模数K有显著的弹性软化，并伴随着显著的超声衰减到K，这是其他模数中急剧下降的峰的温度，表明相变发生在。晶场分析表明，在80℃以下的软化是由于基态和激发的Kramers双态之间存在正的四极-四极耦合常数的能级型四极相互作用。在平均场近似下，我们的晶场模型中出现了自发期望值。在磁有序状态下没有发生四极有序，因为磁性有序的内部磁场解除了四极的简并。然而，我们的实验和计算结果表明，相变的驱动力是Atis类型的铁四极有序，这意味着在零磁场下的磁有序状态下的四极有序。
We conducted ultrasonic measurements to clarify whether a phase transition exists in ErNiAl, a hexagonal compound, below the antiferromagnetic transition temperature,K. We discovered a significant elastic softening of the transverse modulus,, accompanied by a significant ultrasonic attenuation towardK, which is the temperature of a sharp downward peak in other moduli, indicating a phase transition at. The crystal field analysis reveals that the softening ofbelow 80 K is due to an interlevel-type quadrupole interaction with a positive quadrupole-quadrupole coupling constant between the ground and excited Kramers doublets. A spontaneous expectation value ofemerges atin our crystal field model with the mean-field approximation. No quadrupolar ordering occurs in a magnetically ordered state because the degeneracy of quadrupoles is lifted by an internal magnetic field of magnetic ordering. However, our experimental and calculated results suggest that the driving force of the phase transition atis-type ferroquadrupolar ordering, implying a quadrupolar ordering in a magnetically ordered state at zero magnetic field.