Li Hai-Feng, Cao Chongde, Wildes Andrew, Schmidt Wolfgang, Schmalzl Karin, Hou Binyang, Regnault Louis-Pierre, Zhang Cong, Meuffels Paul, Löser Wolfgang, Roth Georg
1] Jülich Centre for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at Institut Laue-Langevin, Boîte Postale 156, F-38042 Grenoble Cedex 9, France [2] Institut für Kristallographie der RWTH Aachen University, D-52056 Aachen, Germany.
Key Laboratory of Space Applied Physics and Chemistry of Ministry of Education, Department of Applied Physics, Northwestern Polytechnical University, Xi'an 710072, P.R. China.
Sci Rep. 2015 Jan 22;5:7968. doi: 10.1038/srep07968.
Identifying the nature of magnetism, itinerant or localized, remains a major challenge in condensed-matter science. Purely localized moments appear only in magnetic insulators, whereas itinerant moments more or less co-exist with localized moments in metallic compounds such as the doped-cuprate or the iron-based superconductors, hampering a thorough understanding of the role of magnetism in phenomena like superconductivity or magnetoresistance. Here we distinguish two antiferromagnetic modulations with respective propagation wave vectors at Q± = (H ± 0.557(1), 0, L ± 0.150(1)) and QC = (H ± 0.564(1), 0, L), where (H, L) are allowed Miller indices, in an ErPd2Si2 single crystal by neutron scattering and establish their respective temperature- and field-dependent phase diagrams. The modulations can co-exist but also compete depending on temperature or applied field strength. They couple differently with the underlying lattice albeit with associated moments in a common direction. The Q± modulation may be attributed to localized 4f moments while the QC correlates well with itinerant conduction bands, supported by our transport studies. Hence, ErPd2Si2 represents a new model compound that displays clearly-separated itinerant and localized moments, substantiating early theoretical predictions and providing a unique platform allowing the study of itinerant electron behavior in a localized antiferromagnetic matrix.
确定磁性的本质，即巡游性或局域性，仍然是凝聚态物理中的一项重大挑战。纯局域磁矩仅出现在磁性绝缘体中，而巡游磁矩或多或少与金属化合物（如掺杂铜酸盐或铁基超导体）中的局域磁矩共存，这妨碍了对磁性在超导或磁阻等现象中所起作用的透彻理解。在这里，我们通过中子散射在ErPd2Si2单晶中区分出两种反铁磁调制，其各自的传播波矢分别为Q± = (H ± 0.557(1), 0, L ± 0.150(1)) 和QC = (H ± 0.564(1), 0, L)，其中(H, L) 为允许的密勒指数，并建立了它们各自依赖于温度和磁场的相图。这些调制可以共存，但也会根据温度或外加磁场强度相互竞争。它们与底层晶格的耦合方式不同，尽管相关磁矩方向相同。我们的输运研究表明，Q±调制可能归因于局域的4f磁矩，而QC调制与巡游导带密切相关。因此，ErPd2Si2代表了一种新的模型化合物，它展示了明显分离的巡游磁矩和局域磁矩，证实了早期的理论预测，并提供了一个独特的平台，可用于研究局域反铁磁矩阵中的巡游电子行为。
