Field dependence of the magnetic spectrum in anisotropic and Dzyaloshinskii-Moriya antiferromagnets. II. Raman spectroscopy (Articolo in rivista)

Type
Label
  • Field dependence of the magnetic spectrum in anisotropic and Dzyaloshinskii-Moriya antiferromagnets. II. Raman spectroscopy (Articolo in rivista) (literal)
Anno
  • 2006-01-01T00:00:00+01:00 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi
  • 10.1103/PhysRevB.74.024416 (literal)
Alternative label
  • L. Benfatto (1); M.B. Silva Neto (2); A. Gozar (3,4); B.S. Dennis (3); G. Blumberg (3); L.L. Miller (5); Seiki Komiya (6); Yoichi Ando (6) (2006)
    Field dependence of the magnetic spectrum in anisotropic and Dzyaloshinskii-Moriya antiferromagnets. II. Raman spectroscopy
    in Physical review. B, Condensed matter and materials physics
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • L. Benfatto (1); M.B. Silva Neto (2); A. Gozar (3,4); B.S. Dennis (3); G. Blumberg (3); L.L. Miller (5); Seiki Komiya (6); Yoichi Ando (6) (literal)
Pagina inizio
  • 024416 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#url
  • http://prb.aps.org/abstract/PRB/v74/i2/e024416 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
  • 74 (literal)
Rivista
Note
  • ISI Web of Science (WOS) (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • (1) CNR-SMC-INFM and Department of Physics, University of Rome \"La Sapienza,\" Piazzale Aldo Moro 5, 00185, Rome, Italy (2) Institute for Theoretical Physics, University of Utrecht, P.O. Box 80.195, 3508 TD, Utrecht, The Netherlands (3) Bell Laboratories, Lucent Technologies, Murray Hill, New Jersey 07974, USA (4) Brookhaven National Laboratory, Upton, New York 11973-5000, USA (5) Churchill H.S./Eugene 4J, Eugene, Oregon 97405, USA (6) Central Research Institute of Electric Power Industry, 2-11-1 Iwato-kita, Komae, Tokyo 201-8511, Japan (literal)
Titolo
  • Field dependence of the magnetic spectrum in anisotropic and Dzyaloshinskii-Moriya antiferromagnets. II. Raman spectroscopy (literal)
Abstract
  • We compare the theoretical predictions of the previous paper on the field dependence of the magnetic spectrum in anisotropic two-dimensional and Dzyaloshinskii-Moriya layered antiferromagnets [L. Benfatto and M. B. Silva Neto, Phys. Rev. B 74, 024415 (2006)], with Raman spectroscopy experiments in Sr(2)CuO(2)Cl(2) and untwinned La(2)CuO(4) single crystals. We start by discussing the crystal structure and constructing the magnetic point group for the magnetically ordered phase of the two compounds, Sr(2)CuO(2)Cl(2) and La(2)CuO(4). We find that the magnetic point group in the ordered phase is the m_mm_ orthorhombic group, in both cases. Furthermore, we classify all the Raman active one-magnon excitations according to the irreducible co-representations for the associated magnetic point group. We find that the in-plane (or Dzyaloshinskii-Moriya) mode belongs to the DA(g) co-representation while the out-of-plane (XY) mode belongs to the DB(g) co-representation. We then measure and fully characterize the evolution of the one-magnon Raman energies and intensities for low and moderate magnetic fields along the three crystallographic directions. In the case of La(2)CuO(4), a weak-ferromagnetic transition is observed for a magnetic field perpendicular to the CuO(2) layers. We demonstrate that from the jump of the Dzyaloshinskii-Moriya gap at the critical magnetic field H(c)similar or equal to 6.6 T one can determine the value of the interlayer coupling J(perpendicular to)/J similar or equal to 3.2x10(-5), in good agreement with previous estimates. We furthermore determine the components of the anisotropic gyromagnetic tensor as g(s)(a)=2.0, g(s)(b)=2.08, and the upper bound g(s)(c)=2.65, also in very good agreement with earlier estimates from magnetic susceptibility. For the case of Sr(2)CuO(2)Cl(2), we compare the Raman data obtained in an in-plane magnetic field with previous magnon-gap measurements done by electron spin resonance (ESR). Using the very low magnon gap estimated by ESR (similar to 0.05 meV), the data for the one-magnon Raman energies agree reasonably well with the theoretical predictions for the case of a transverse field (only hardening of the gap). On the other hand, an independent fit of the Raman data provides an estimate for g(s)similar or equal to 1.98 and gives a value for the in-plane gap larger than the one measured by ESR. Finally, because of the absence of the Dzyaloshinskii-Moriya interaction in Sr(2)CuO(2)Cl(2), no field-induced modes are observed for magnetic fields parallel to the CuO(2) layers in the Raman geometries used, in contrast to the situation in La(2)CuO(4). (c) 2006 American Institute of Physics. (literal)
Prodotto di
Autore CNR

Incoming links:


Autore CNR di
Prodotto
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#rivistaDi
data.CNR.it