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2007 | 111 | 1 | 173-177
Article title

Anharmonicity and Weak Mode Assignment in La_{2-x}Sr_xCuO_4, with Oxygen Isotopic Substitution

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EN
Abstracts
EN
The oxygen isotope effect on the first- and second-order Raman active modes of high-quality La_{2-x}Sr_xCu^{16,18}O_4 (80% substitution ^{16}O by ^{18}O) polycrystalline compounds with x=0.00, 0.015 was investigated at low temperatures. In the second-order Raman scattering several weak and strong peaks were observed and assigned to oxygen atom vibrations. With the isotopic substitution the apex oxygen mode follows quite well the mass harmonic law at all temperatures studied, while the soft mode is anharmonic in the temperature range of 77-180 K and for higher temperatures its anharmonicity is strongly increased. The temperature dependence of the energy of the soft mode for x=0.0 shows also a modification at≈180 K and an abnormal behaviour at≈280 K, which may be related with the transition to the antiferromagnetic phase.
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Contributors
author
  • Department of Physics, National Technical University, Athens 157 80, Greece
author
  • Department of Physics, National Technical University, Athens 157 80, Greece
author
  • Department of Physics, National Technical University, Athens 157 80, Greece
author
  • Department of Physics, National Technical University, Athens 157 80, Greece
author
  • Paul Scherrer Institut (PSI) WLGA, Villigen PSI 5232, Switzerland
References
  • 1. B. Keimer, N. Belk, R.J. Birgeneau, A. Cassanho, C.Y. Chen, M. Greven, M.A. Kastner, A. Aharony, Y. Endoh, R.W. Erwin, G. Shirane, Phys. Rev. B. 46. 14034, 1992
  • 2. S. Sugai, Phys. Rev. B. 39. 4306, 1989
  • 3. W.M. Weber, C.R. Peters, E.M. Logothetis, J. Opt. Soc. Am.. 6. 455, 1989
  • 4. W.M. Weber, C.R. Peters, B.M. Wanklyn, C. Chen, B.E. Watts, Phys. Rev. B. 38, 917, 1988
  • 5. D. Lampakis, Ph.D. Thesis, National Technical University of Athens, Department of Physics, Athens 2002, p. 100
Document Type
Publication order reference
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YADDA identifier
bwmeta1.element.bwnjournal-article-appv111n123kz
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