Magnetic anisotropy and ferromagnetic correlations above the Curie temperature in Eu2CuSi3 single crystals

• Verfasst von: Cao, Chongde [VerfasserIn]
• Verfasst von: Klingeler, Rüdiger [VerfasserIn]
• Verfasst von: Vinzelberg, H. [VerfasserIn]
• Verfasst von: Leps, Norman Uwe [VerfasserIn]
• Verfasst von: Löser, W. [VerfasserIn]
• Verfasst von: Behr, G. [VerfasserIn]
• Verfasst von: Muranyi, F. [VerfasserIn]
• Verfasst von: Kataev, V. [VerfasserIn]
• Verfasst von: Büchner, B. [VerfasserIn]
• Titel: Magnetic anisotropy and ferromagnetic correlations above the Curie temperature in Eu2CuSi3 single crystals
• Verf.angabe: C.D. Cao, R. Klingeler, H. Vinzelberg, N. Leps, W. Löser, G. Behr, F. Muranyi, V. Kataev, and B. Büchner
• E-Jahr: 2010
• Jahr: 27 October 2010
• Umfang: 7 S.
• Fussnoten: Im Titel sind die Zahlen 2 und 3 tiefgestellt ; Gesehen am 29.03.2023
• Titel Quelle: Enthalten in: Physical review / B
• Ort Quelle: College Park, Md. : APS, 1970
• Jahr Quelle: 2010
• Band/Heft Quelle: 82(2010), 13, Artikel-ID 134446, Seite 1-7
• ISSN Quelle: 1550-235X
• DOI: doi:10.1103/PhysRevB.82.134446
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1840467134

Abstract

Magnetization M(T,B), specific heat cp(T), and electrical resistivity ρ(T,B) show ferromagnetic ordering in Eu2CuSi3 single crystals below the Curie temperature TC=34 K. Temperature T and magnetic field B-dependent M(T,B) data give evidence for a sizable magnetic anisotropy in the AlB2-derived hexagonal structure at T<TC. The increase in |dM/dT| at TC for B=50 mT along the easy magnetic c axis (⟨001⟩) is more than twice as large as for B along the a axis (⟨010⟩). The analysis of cp(T) in the magnetically ordered phase reveals signatures of a spin-reorientation process at T≈10 K below which the magnetic anisotropy in M(T,B) almost vanishes. Measurements of electron-spin resonance (ESR) on Eu2+ ions reveal the anisotropy of the resonance field and the additional narrowing of the ESR signal at T<100 K that prove appreciable short-range ferromagnetic correlations far above TC. These lead to a large negative magnetoresistance observed in the ρ(T,B) measurements even up to a temperature T≈100 K. Below 50 K the ESR line starts to split due to the emergence of two magnetically nonequivalent Eu sites. The onset of magnetic order is manifested in the ESR spectrum by nucleation of a third line. Below T≈10 K, where thermodynamic data suggest a transformation of the ordered spins to a state with strongly reduced anisotropy, the ESR spectrum evolves into a featureless broad asymmetric peak.