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Europium mixed-valence, long-range magnetic order, and dynamic magnetic response in EuCu2 (Six Ge1-x )2

Journal Article · · Physical Review B
 [1];  [2];  [3];  [4];  [5];  [6];  [7];  [8];  [8];  [9];  [10];  [11]
  1. Forschungszentrum JulichGmbH, Garching (Germany)
  2. Frank Lab. of Neutron Physics, Moscow Region (Russia)
  3. National Research Centre "Kurchatov Institute", Moscow (Russia); National Research Nuclear Univ. MEPhI (Moscow Engineering Physics Institute), Moscow (Russia)
  4. Lab. Leon Brillouin-UMR12 CNRS-CEA, Gif-sur-Yvette (France)
  5. National Research Nuclear Univ. MEPhI (Moscow Engineering Physics Institute), Moscow (Russia)
  6. National Research Nuclear Univ. MEPhI (Moscow Engineering Physics Institute), Moscow (Russia); European XFEL GmbH, Schenefeld (Germany)
  7. I Kant Baltic Federal Univ., Kaliningrad (Russia); Institute for Nuclear Research RAS, Moscow (Russia)
  8. Institute Laue-Langevin, Grenoble Cedex (France)
  9. Forschungszentrum Julich GmbH, Julich (Germany)
  10. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  11. Moscow State Univ., Moscow (Russia)
In mixed-valence or heavy-fermion systems, the hybridization between local f orbitals and conduction band states can cause the suppression of long-range magnetic order, which competes with strong spin uctuations. Ce- and Yb-based systems have been found to exhibit fascinating physical properties (heavy-fermion superconductivity, non-Fermi-liquid states, etc.) when tuned to the vicinity of magnetic quantum critical points by use of various external control parameters (temperature, magnetic eld, chemical composition). Recently, similar effects (mixed-valence, Kondo uctuations, heavy Fermi liquid) have been reported to exist in some Eu-based compounds. Unlike Ce (Yb), Eu has a multiple electron (hole) occupancy of its 4f shell, and the magnetic Eu2+ state (4f7) has no orbital component in the usual LS coupling scheme, which can lead to a quite different and interesting physics. In the EuCu2(SixGe1-x)2 series, where the valence can be tuned by varying the Si/Ge ratio, it has been reported that a significant valence uctuation can exist even in the magnetic order regime. This paper presents a detailed study of the latter material using different microscopic probes (XANES, Mossbauer spectroscopy, elastic and inelastic neutron scattering), in which the composition dependence of the magnetic order and dynamics across the series is traced back to the change in the Eu valence state. In particular, the results support the persistence of valence uctuations into the antiferromagnetic state over a sizable composition range below the critical Si concentration xc ≈ 0:65. In conclusion, the sequence of magnetic ground states in the series is shown to re ect the evolution of the magnetic spectral response.
Research Organization:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE; USDOE Office of Science (SC)
Grant/Contract Number:
AC05-00OR22725
OSTI ID:
1331099
Alternate ID(s):
OSTI ID: 1330601
Journal Information:
Physical Review B, Journal Name: Physical Review B Journal Issue: 19 Vol. 94; ISSN 2469-9950; ISSN PRBMDO
Publisher:
American Physical Society (APS)Copyright Statement
Country of Publication:
United States
Language:
English

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Cited By (1)

Influence of europium doping on magnetic properties of 3D topological semimetal Cd3As2 from ESR data journal January 2018

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