- Access by Xinjiang University
Microscopic Theory of Far-Infrared Two-Magnon Absorption in Antiferromagnets. I. Perturbation-Theory Search and Application of Fourth-Order Process to Fe
Phys. Rev. 149, 423 – Published 16 September, 1966
DOI: https://doi.org/10.1103/PhysRev.149.423
Abstract
A microscopic description of the mechanism responsible for an absorption line observed in antiferromagnetic Fe at 154 is proposed. The mechanism appears to account for the properties of the observed line which are described in the preceding paper. In isolating the proposed mechanism, we set up a model which includes magnon, phonon, exciton, and photon fields and their interactions. The mechanism involves an indirect coupling between odd-parity excitons and magnons which we have previously called the odd-exciton-magnon interaction. This coupling is a consequence of the combined action of the spin-orbit interaction and the quadrupole-dipole part of the spin-orbit interaction. A search through fourth order in perturbation theory in this model yields several other possible processes. Our estimates indicate that the process we propose is the largest contributor in Fe and that a third process, involving a phonon, may be contributing to the absorption intensity. The proposed process is used to derive the spin Hamiltonian used in the preceding paper and to estimate the intensity and polarization ratio.
References (22)
- I. Silvera, thesis, University of California, Berkeley, 1965 (unpublished)
- I. Silvera and M. Tinkham, Bull. Am. Phys. Soc. 1, 714 (1964)
- P. L. Richards, Bull. Am. Phys. Soc. 10, 33 (1965)
- R. C. Ohlman and M. Tinkham, Phys. Rev. 123, 425 (1961)
- J. W. Halley and I. Silvera, preceding paper, Phys. Rev. 149, 415 (1966)
- J. W. Halley and I. Silvera, Phys. Rev. Letters 15, 654 (1965)
- Y. Tanabe, T. Moriya, and S. Sugano, Phys. Rev. Letters 15, 1023 (1965)
- T. Moriya et al., J. Phys. Soc. Japan 11, 211 (1956)
- C. Moore, Natl. Bur. Std. U. S. Circ. 467, Vol. II, 61 (1952)
- J. M. Ziman, Electrons and Phonons (Clarendon Press, Oxford, England, 1962), p. 50
- P. W. Anderson, Concepts in Solids (W. A. Benjamin, Inc., New York, 1963), p. 132
Omitted endnote
Omitted endnote
- Tanabe et al. ([7])
Omitted endnote
- E. H. Jacobsen and K. W. H. Stevens, Phys. Rev. 129, 2036 (1962)
- P. W. Anderson, Phys. Rev. 79, 350 (1950)
- Y. Tanabe and S. Sugano, J. Phys. Soc. Japan 9, 753 (1954)
- A. Abragam and F. Boutron, Compt. Rend. 252, 2404 (1961)
- S. J. Allen Jr., R. Loudon, and P. L. Richards, Phys. Rev. Letters 16, 463 (1966)
- P. L. Richards, Bull. Am. Phys. Soc. 10, 33 (1965)
- R. L. Greene, D. D. Sell, W. M. Yen, A. L. Schawlow, and R. M. White, Phys. Rev. Letters 15, 656 (1965) P. G. Russell, D. S. McClure, and J. W. Stout, 16, 176 (1966)