Symmetry of phonon, magnetic, and spin-phonon excitations in GdSr2RuCu2O8 single crystals

V. G. Hadjiev, J. Bäckström, V. N. Popov, M. N. Iliev, R. L. Meng, Y. Y. Xue, C. W. Chu, C. W. Chu

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17 Citations (Scopus)

Abstract

We present a polarized Raman scattering study of GdSr2RuCu2O8 single crystals. In this compound, the RuO6 octahedra are rotated around the c axis that in turn gives some Raman activity of the oxygen (ORu) vibrations at 265 cm-1 (A1g), 411 cm-1 (B2g) and 607 cm-1 (B1g). These vibrations, as well as those of the apical oxygen of RuO6 at 654 cm-1 (A1g) and the Cu-plane oxygen at 318 cm-1 (B2g), clearly respond to the onset of magnetic ordering at Tm≈140 K. In particular, the 265 cm-1 mode hardens anomalously with decreasing temperature below Tm. Notably, the corresponding phonon line is absent in the Raman spectra of GdSr2NbCu2O8 (Nb5+:4d0), a compound isomorphic to GdSr2RuCu2O8 (Ru5+:4d3). We argue that the eigenvector of the 265 cm-1 phonon (rotational mode) facilitates efficient modulation of the Ru(t1g)-ORu(p) bands. This modulation gives both Raman scattering strength to the 265 cm-1 mode and strong spin-phonon coupling.

Original languageEnglish
Article number134304
Pages (from-to)1343041-1343046
Number of pages6
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume64
Issue number13
Publication statusPublished - 2001 Oct 1

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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