Study of Internal Field in the Magnetic Ordered Static of the rare-earth hexaboride by the Nuclear Magnetic Resonance

CeB_6是一种具有反铁四极有序性的化合物。最近，Sakai等人揭示了AFQ有序态中神秘性质的起源，他们引入了AF八极（AFO）相互作用。然而，其微观机制尚未阐明。为了阐明CeB_6中多极相互作用的特殊性质，我们研究了Ce_xR_<1-x>B_6（R=Nd，Gd）系统的磁性、输运和热性质，发现在高温下，电阻率存在与Ce_xLa_ B_6相似的杂质近藤效应<1-x>。我们还发现，近藤效应继续存在，即使在长程AF磁有序状态，虽然Ce离子有助于AF磁有序。Ce离子的基态在小的x区域中，当x&gt;0.3时是定域态，而当0.1&lt;x&lt;0.3时是近藤单态。我们期望本研究结果能促进近藤效应的研究 ...更多信息 在长程AF磁有序化中起作用。完成了Ce_xNd_ B_6的磁相图<1-x>，发现在x=0.5时存在第II相，x&lt;0.4时消失。结果表明，当x小于0.5时，AFQ相互作用迅速被抑制，而Ce_xLa_ B_6中<1-x>的第二相直到x ≤ 0.3时仍存在。我们研究了Ce_xGd_<1-x>B_6体系，发现Gd掺杂抑制AFQ相互作用，但增强了AFO相互作用。我们还观察到了异常磁场诱导的AF磁分量，这是我们通过对4亚晶格模型的平均场计算所预测的。通过这些研究，我们可以阐明第II和第III相的异常性质是AFQ、AFO和AF交换相互作用竞争的结果，我们发现Yb_<1-x>La_xB_6在小x区在T = 150K时表现出铁磁有序。这一工作将为阐明CaB_6体系铁磁有序的起源提供线索。少

CeB_6 is a famous compound showing a mysterious Antiferro-Quadrupolar(AFQ) ordering for 20 years. Very recently, the origin of the mysterious nature in the AFQ ordered state was revealed by Sakai et al. who introduced the AF octupolar (AFO) interaction. However, the microscopic mechanism has not yet been clarified. In order to clarify the unusual nature of the multipolar interaction in CeB_6, we have studied the magnetic, transport and thermal properties of Ce_xR_<1-x>B_6(R=Nd, Gd) system.We found that the impurity Kondo effect exists at high temperatures in the electrical resistivity which is quite similar to that in Ce_xLa_<1-x>B_6. We also found that the Kondo effect continues to exist even in the long range AF magnetic ordered sate although the Ce ion contributes to the AF magnetic ordering. The ground state of the Ce ion in a small x region and for x>0.3 is the localized state but the Kondo singlet for 0.1<x<0.3. We expect that the present results promote the study of the Kondo ef … More fect in the long range AF magnetic ordering. The magnetic phase diagram of Ce_xNd_<1-x>B_6 was completed and found that phase II exists down to x=0.5 and disappears foe x<0.4. From these results, the AFQ interaction is suppressed rapidly with decreasing x below x=0.5, being different from the case of Ce_xLa_<1-x>B_6 where phase II continues to exist down to x〜0.3.We studied the Ce_xGd_<1-x>B_6 system and found that the Gd doping suppresses the AFQ interaction but enhances the AFO one.We analyzed the NMR results in phases II and III of CeB_6 and could succeeded to separate the contribution from the AF octupolar and AFQ moments. We also could observe the unusual magnetic field induced AF magnetic component, which we predicted by the mean field calculation for the 4 sublattice model. Through these studies, we could clarify the origin of the unusual properties in phases II and III as the result of the competition between three of the AFQ, AFO and AF exchange interactions.We found that Yb_<1-x>La_xB_6 in a small x region exhibits the ferromagnetic ordering at T〜150K. This work will be the clue to clarify the origin of the ferromagnetic ordering in CaB_6 system. Less