Spin Order and Excitations in Triangular Antiferromagnet La2Ca2MnO7

Wei Bao; Y. X. Wang; Y. Qiu; K. Li; J. H. Lin; J. R. D. Copley; R. W. Erwin; B. S. Dennis; A. P. Ramirez

Spin Order and Excitations in Triangular Antiferromagnet La2Ca2MnO7

Strongly Correlated Electrons 2009-10-13 v1 Statistical Mechanics

Authors: Wei Bao , Y. X. Wang , Y. Qiu , K. Li , J. H. Lin , J. R. D. Copley , R. W. Erwin , B. S. Dennis , A. P. Ramirez

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Abstract

We report a spin S = 3/2 triangular antiferromagnet with nearest-neighbor coupling J = 0.29 meV in La2Ca2MnO7. A genuinely two-dimensional, three-sublattice order develops below 2.80 K << the Weiss constant (25 K). The spin excitations deviate substantially from linear spin-wave theory, suggesting that magnon breakdown occurs in the material. Such a breakdown has been anticipated in recent theoretical studies, although the excitation spectrum remains to be accounted for.

Keywords

frustrated magnetism spin excitations in condensed matter magnetism

Cite

@article{arxiv.0910.1904,
  title  = {Spin Order and Excitations in Triangular Antiferromagnet La2Ca2MnO7},
  author = {Wei Bao and Y. X. Wang and Y. Qiu and K. Li and J. H. Lin and J. R. D. Copley and R. W. Erwin and B. S. Dennis and A. P. Ramirez},
  journal= {arXiv preprint arXiv:0910.1904},
  year   = {2009}
}

Comments

5 pages, 4 figures plus a supplementary figure

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