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Magnetic properties of Yb Mo O and Gd Mo O from rare earth Mössbauer measurements

  • J.A. Hodges
  • P. Bonville
  • A. Forget
  • J.P. Sanchez
  • P. Vulliet
  • M. Rams
  • K. Królas

Abstract:

Using 170Yb and 155Gd Mössbauer measurements down to 0.03 K, we have examined the semiconducting pyrochlore Yb2Mo2O7 where the Mo intra-sublattice interaction is anti-ferromagnetic and the metallic pyrochlore Gd2Mo2O7 where this interaction is ferromagnetic. Additional information was obtained from susceptibility, magnetisation and 172Yb perturbed angular correlation measurements. The microscopic measurements evidence lattice disorder which is important in Yb2Mo2O7 and modest in Gd2Mo2O7. Magnetic irreversibilities occur at 17 K in Yb2Mo2O7 and at 75 K in Gd2Mo2O7 and below these temperatures the rare earths carry magnetic moments which are induced through couplings with the Mo sublattice. In Gd2Mo2O7, we observe the steady state Gd hyperfine populations at 0.027 K are out of thermal equilibrium, indicating that Gd and Mo spin fluctuations persist at very low temperatures. Frustration is thus operative in this essentially isotropic pyrochlore where the dominant Mo intra-sublattice interaction is ferromagnetic.

PACS. 76.80.+y Mössbauer effect; other gamma-ray spectroscopy – 75.50.Lk Spin glasses and other random magnets – 75.30.-m Intrinsic properties of magnetically ordered materials 

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Copyright information

© EDP Sciences, Springer-Verlag 2003

Authors and Affiliations

  • J.A. Hodges
    • 1
  • P. Bonville
    • 1
  • A. Forget
    • 1
  • J.P. Sanchez
    • 2
  • P. Vulliet
    • 2
  • M. Rams
    • 3
  • K. Królas
    • 3
  1. 1.Commissariat à l'Énergie Atomique, Centre d'Études de Saclay, Service de Physique de l'État Condensé, 91191 Gif-sur-Yvette, FranceFR
  2. 2.Commissariat à l'Énergie Atomique, Centre d'Études de Grenoble, Service de Physique Statistique, Supraconductivité et Magnétisme, 38054 Grenoble, FranceFR
  3. 3.Institute of Physics, Jagiellonian University, 30-059 Kraków, PolandPL

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