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Two-Magnon Spectra of Ferromagnets

  • P. D. Loly
Part of the NATO Advanced Study Institutes Series book series (NSSB, volume 35)

Abstract

Historically the foundations of the contemporary study of two-magnon states were laid by Wortis1 in 1963 when he located the two-magnon bound states of the n.n. isotropic hypercubic Heisenberg ferromagnet, established the connection with bound states of the corresponding Ising problem and gave a spin Green function formalism that exactly described the 2-magnon problem in ferromagnets at T=0°K. The conclusion that 2-magnon bound states in the n.n. s.c. case only occurred at large values of the total pair wavevector \( \left( {\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\rightharpoonup}$}} {K} = {{\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\rightharpoonup}$}} {K} }_1} + {{\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\rightharpoonup}$}} {K} }_2}} \right) \) and with an energy too large to affect the low temperature thermodynamics did not offer much hope for observing these effects. The scene shifted to broad peaks detected in optical studies of transparent antiferromagnets2 in 1966 (infrared absorption, Raman scattering) which stimulated \( \overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\rightharpoonup}$}} {K} = 0 \) calculations that eventually attained good agreement with experiment when magnon-magnon interactions were properly included by Elliott and Thorpe3. Even at T=0°K the antiferromagnetic formulation is subject to decoupling approximations in contrast to the ferromagnet.

Keywords

Raman Resonance Biquadratic Exchange Ising Problem Itinerant Magnet Ising Calculation 
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.

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References

  1. 1.
    M. Wortis, Phys. Rev. 132, 85 (1963).MathSciNetADSCrossRefGoogle Scholar
  2. 2.
    See the review by P.A. Fleury and S.P.S. Porto, J. Appl. Phys. 39, 1035 (1968).ADSCrossRefGoogle Scholar
  3. 3.
    R.J. Elliott and M.F. Thorpe, J. Phys. C. 2, 1630 (1969).ADSCrossRefGoogle Scholar
  4. 4.
    M.F. Thorpe, Phys. Rev. B 4, 1608 (1971).ADSCrossRefGoogle Scholar
  5. 5.
    P.D. Loly, B.J. Choudhury and W.R. Fehlner, Phys. Rev. B 11, 1996 (1975).ADSCrossRefGoogle Scholar
  6. 6.
    B.J. Choudhury and P.D. Loly, A.I.P. Conf. Proc. 24, 180 (1975).ADSGoogle Scholar
  7. 7.
    P.D. Loly and B.J. Choudhury, Phys. Rev. B 13, 4019 (1976).ADSCrossRefGoogle Scholar
  8. 8.
    P.D. Loly p. 278 Proc. of Third International Conference on Light Scattering from Solids, Campinas, Brazil, published by Flammarion, 1976.Google Scholar
  9. 9.
    S-T Chiu-Tsao, P.M. Levy and C. Paulson, Phys. Rev. B 12, 1819 (1975).ADSCrossRefGoogle Scholar
  10. 10.
    A.M. Bonnot and J. Hanus, Phys. Rev. B 7, 2207 (1973).ADSCrossRefGoogle Scholar
  11. 11.
    D.A. Pink and P. Tremblay, Can. J. Phys. 50, 1728 (1972)ADSCrossRefGoogle Scholar
  12. 11a.
    and D.A. Pink and R. Ballard, Can. J. Phys. 52, 33 (1974).ADSCrossRefGoogle Scholar
  13. 12.
    R. Silberglitt and J.B. Torrance, Phys. Rev B 2, 772 (1970).ADSCrossRefGoogle Scholar

Copyright information

© Plenum Press, New York 1978

Authors and Affiliations

  • P. D. Loly
    • 1
  1. 1.Department of PhysicsUniversity of ManitobaWinnipegCanada

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