Quantum criticality in NbFe₂

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• 作者：M. Brando ; D. Moroni-Klementowicz ; C. Albrecht and F.M. Grosche
• 关键词：Quantum criticality ; Strongly correlated metals
• 刊名：Physica B
• 出版年：2006
• 出版时间：1 May 2006
• 年：2006
• 卷：378-380
• 期：Complete
• 页码：111-112
• 全文大小：224 K

文摘

The C14 Laves phase NbFe₂ is one of the few reported low temperature antiferromagnets among the transition metal compounds. It represents an interesting candidate for a study of antiferromagnetic quantum criticality in a strictly itinerant system. Because the nature of the ordered state in stoichiometric NbFe₂ is still controversial—neutrons fail to pick up signatures of magnetic order, which are, however, detected using NMR—we have investigated the thermodynamic and transport properties of NbFe₂ in a range of samples with near-stoichiometric composition. A large uniform susceptibility χ of the order of e52009c50a74e71401316510381a640"" title=""Click to view the MathML source"">1.8×10^-2 (SI), which corresponds to a record Stoner enhancement factor of about 150, places all samples close to the threshold of ferromagnetism. Strongly field-dependent anomalies in the heat capacity and χ, however, point at spin-density-wave order below in stoichiometric NbFe₂, indicating an intriguing interplay between ferromagnetism and antiferromagnetism. Slightly Nb-rich samples, which show no evidence of magnetic order, display distinct deviations from Fermi-liquid behaviour, consistent with close proximity to a magnetic quantum critical point.