Advertisement

Hyperfine Interactions

, Volume 64, Issue 1–4, pp 331–349 | Cite as

Rare earth paramagnetism, as studied by μSR

  • Erik B. Karlsson
Invited Paper

Abstract

Some recent result of muon spin relaxation measurements in rare earth metals and intermetallic compounds are reviewed. Special emphasis is put on measurements that relate to the properties of correlated regions of spins existing relatively far above the ordering temperature in the rare earth ions. As far as comparable data from paramagnetic neutron scattering exist, they will be discussed in the same framework. For each temperature the correlated regions (or short-lived magnetic clusters) are characterized by their size, possible anisotropy with respect to the crystalline axes and their lifetime. The actual form of the interaction between the rare earth spins themselves and with the crystal fields determine the temperature dependence of these properties; a strong dipole interaction can, for instance, be expected to change the critical behaviour nearT c . Much of the time will be devoted to experiments on Gd-metal where there are experimental indications that several interesting phenomena occur: (1) a strong effect of a cross-over from a non-conserved dynamics (dipolar) regime to a conserved (exchange dominated) regime some 10 K aboveT c , (2) an anisotropy of the magnetic clusters with respect to the hexagonalc-axis, and (3), a persistence of spin correlations far aboveT c . Some attempts to correlate the rare earth spin relaxation times measured in this region with cluster lifetimes deduced from neutron scattering will be reviewed, as well as a model for understanding these lifetimes in terms of temperature dependent cluster wall motion, which is determined by exchange and magnetic anisotropy parameters. Effects of possible quantum correlations originating from the “spin system+bath” interaction will be mentioned.

Keywords

Rare Earth Magnetic Anisotropy Spin Relaxation Muon Spin Spin Relaxation Time 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. [1]
    C. Günther and I. Lindgren, in:Perturbed Angular Correlations, eds. E. Karlsson, E. Matthias and K. Siegbahn (North-Holland Publ., Co., Amsterdam, 1964) p. 355.Google Scholar
  2. [2]
    Y. Barash, J. Barak and N. Kaplan, Phys. Rev. B25 (1982) 6616.CrossRefADSGoogle Scholar
  3. [3]
    B.G. Silbernagel, V. Jaccarino, P. Pincus and J.H. Wernick, Phys. Rev. Lett. 20 (1968) 1091.CrossRefADSGoogle Scholar
  4. [4]
    A.R. Chowdhury, G.S. Collins and C. Hohenemser, Phys. Rev. B30 (1984) 6277.CrossRefADSGoogle Scholar
  5. [5]
    G.S. Collins, A.R. Chowdhury and C. Hohenemser, Phys. Rev. B33 (1986) 4747.CrossRefADSGoogle Scholar
  6. [6]
    E. Karlsson, Phys. Rep. 82 (1982) 272.CrossRefADSGoogle Scholar
  7. [7]
    I.A. Campbell, J. Physique Lett. 45 (1984) L27.ADSGoogle Scholar
  8. [8]
    O. Hartmann, E. Karlsson, R. Wäppling, J. Chappert, A. Yaouanc, L. Asch and G.M. Kalvius, J. Phys: Met. Phys. 16 (1986) 1593.CrossRefADSGoogle Scholar
  9. [9]
    B.I. Halperin and P.C. Hohenberg, Phys. Rev. 177 (1969) 952.CrossRefADSGoogle Scholar
  10. [10]
    A.M. Gottlieb and P. Heller, Phys. Rev. B3 (1971) 3615.CrossRefADSGoogle Scholar
  11. [11]
    E. Wäckelgård, O. Hartmann, E. Karlsson, R. Wäppling, L. Asch, G.M. Kalvius, J. Chappert and A. Yaouanc, Hyp. Int. 31 (1986) 325.Google Scholar
  12. [12]
    S.G. Barsov et al., Hyp. Int. 31 (1986) 339.Google Scholar
  13. [13]
    S.G. Barsov et al., Hyp. Int. 18 (1983) 485.CrossRefGoogle Scholar
  14. [14]
    O. Hartmann, S.W. Harris, R. Wäppling, G.M. Kalvius, L. Asch, P. Dalmas de Réotier and A. Yaouanc, Hyp. Int. 64 (1990) 381.Google Scholar
  15. [15]
    P. Dalmas de Réotier, J.P. Sanchez, P. Vulliet, A. Yaouanc, S.W. Harris, O. Hartmann, E. Karlsson, R. Wäppling, B. Barbara, B. Gorges, R. Lemaire, Ph. L'Héritier, A. Weidinger and P.C. Gubbens, Hyp. Int. 64 (1990) 389.Google Scholar
  16. [16]
    O. Hartmann et al., private communication.Google Scholar
  17. [17]
    O. Hartmann, R. Wäppling, A. Yaouanc, P. Dalmas de Réotier, B. Barbara, K. Aggarwal, L. Asch, A. Kratzer, G.M. Kalvius, F.J. Litterst, F.N. Gygax, B. Hitti, E. Lippelt and A. Schenck, Hyp. Int. 49 (1989) 95.Google Scholar
  18. [18]
    M. Löwenhaupt, B. Frick, U. Walter and E. Holland-Moritz, J. Magn. Magn. Mat. 31–34 (1983) 187.CrossRefGoogle Scholar
  19. [19]
    T. Moriya, Prog. Theor. Phys. 16 (1956) 41.Google Scholar
  20. [20]
    E. Wäckelgård, O. Hartmann, E. Karlsson, R. Wäppling, L. Asch, G.M. Kalvius, J. Chappert and A. Yaouanc, Hyp. Int. 31 (1986) 325.Google Scholar
  21. [21]
    O. Hartmann, R. Wäppling, E. Karlsson, G.M. Kalvius, L. Asch, F.J. Litterst, K. Aggarwal, K.H. Münch, F.N. Gygax and A. Schenck, private communication.Google Scholar
  22. [22]
    D.J.W. Geldart, P. Hargraves, N.M. Fujiki and R.A. Dunlap, Phys. Rev. Lett. 62 (1989) 2728.CrossRefADSGoogle Scholar
  23. [23]
    O. Hartmann, S.W. Harris, R. Wäppling, G.M. Kalvius, L. Asch, P. de Réotier and A. Yaouanc, Hyp. Int. 64 (1990) 381.Google Scholar
  24. [24]
    C.D. Graham, J. Appl. Phys. 34 (1963) 1341.CrossRefGoogle Scholar
  25. [25]
    J.W. Cable, R.M. Nicklow and N. Wakabayashi, J. Magn. Magn. Mat. 54–57 (1987) 1173.Google Scholar
  26. [26]
    J. Kötzler, J. Magn. Magn. Mat. 54–57 (1987) 649.Google Scholar
  27. [27]
    V.Yu. Yushankai, Hyp. Int. 50 (1989) 775.Google Scholar
  28. [28]
    J. Kötzler, Phys. Rev. Lett. 51 (1983) 833.CrossRefADSGoogle Scholar
  29. [29]
    J. Kötzler, D. Görlitz, F. Mezei and B. Farago, Europhys. Lett. 1 (1986) 675.ADSGoogle Scholar
  30. [30]
    J.W. Cable and R.M. Nicklow, Phys. Rev. B39 (1989) 11732.CrossRefADSGoogle Scholar
  31. [31]
    W. Döring, Z. Naturforschung 3a (1948) 373.Google Scholar
  32. [32]
    F. Keffer, in:Handbuch der Physik, ed. S. Flügge Band xviii/2 (Springer Verlag, Berlin, 1966) p. 1.Google Scholar
  33. [33]
    E.M. Chudnowski, private communication to E. Karlsson (Grenoble, 1989).Google Scholar
  34. [34]
    E.J. Brändas and C.A. Chatzidimitriou-Dreismann, in:Lecture Notes in Physics Vol. 325, eds. E. Brändas and N. Elander (Springer Verlag, Berlin, 1989), p. 485–540.Google Scholar
  35. [35]
    C.A. Chatzidimitriou-Dreismann and E.J. Brändas, Int. J. Quant. Chem. 37 (1990) 1536.CrossRefGoogle Scholar
  36. [36]
    E. Karlsson, C.A. Chatzidimitriou-Dreismann and E.J. Brändas, Hyp. Int. 64 (1990) 351.Google Scholar
  37. [37]
    C.A. Chatzidimitriou-Dreismann, E.J. Brändas and E. Karlsson, Phys. Rev. B 42 (1990) 2704.CrossRefADSGoogle Scholar

Copyright information

© J.C. Baltzer A.G. Scientific Publishing Company 1990

Authors and Affiliations

  • Erik B. Karlsson
    • 1
  1. 1.Dept. of PhysicsUniversity of UppsalaUppsalaSweden

Personalised recommendations