Direct observation of the multiple spin gap excitations in two-dimensional dimer system SrCu2(BO3)2

Hiroyuki Nojiri, Hiroshi Kageyama, Kenzo Onizuka, Yutaka Ueda, Mitsuhiro Motokawa

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115 Citations (Scopus)


Various spin-gap excitations have been observed in the two-dimensional dimer system SrCu2(BO3)2 by ESR. The zero-field energy gap of the lowest spin-gap excitation shows a splitting into two triplet modes and the energy splitting clearly depends on the magnetic field orientation. A zero-field splitting is also found between the Sz = +1 and Sz = -1 branches of each triplet. These behaviors are qualitatively explained by considering the anisotropic inter-dimer and intra-dimer exchange couplings. The averaged value of the lowest spin-gap energy is determined to be 722±2 GHz (34.7 K). We have also found a second spin-gap excitation at 1140 GHz (54.7 K), which indicates that the inter-dimer coupling is strong. Besides these modes, a number of gapped ESR absorptions are found and we propose that these excitations are caused by the localized nature of the excited state in the present system.

Original languageEnglish
Pages (from-to)2906-2909
Number of pages4
Journaljournal of the physical society of japan
Issue number9
Publication statusPublished - 1999 Sep


  • ESR
  • High magnetic field
  • Magnetic excitation
  • Spin gap
  • SrCu(BO)

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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