THz ESR study of Spinel Compound GeCo2O4

Susumu Okubo, Hitoshi Ohta, Tatsuya Ijima, Tatsuya Yamasaki, Weimin Zhang, Shigeo Hara, Shinichi Ikeda, Hiroyuki Oshima, Miwako Takahashi, Keisuke Tomiyasu, Tadataka Watanabe

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3 Citations (Scopus)


We performed terahertz ESR measurements of spin frustrated spinel compound GeCo2O4 using pulsed magnetic fields of up to 40 T. A very broad EPR absorption line was observed at 86 K. The g-values at 86 K were estimated to be g=5.26±0.07, 5.16±0.12 and 4.98±0.07 for B//[111], [100] and [110], respectively. High-field ESR measurements revealed complicated phase structures and a field-induced magnetic phase below 3 K. Critical fields of magnetic phases at 1.8 K for B//[111] were observed at 1.8 T, 5.0 T, 8.6 T, 11.0 T and 12.9 T for B//[111]. An energy gap of 300 GHz (=14.4 K=1.24 meV), which was related to the lattice deformation, was observed for B//[111]. The zero field gap of ω4 mode, which is considered to be a singlet-triplet excitation of the di-tetramer, was estimated to be 1120 GHz.

Original languageEnglish
Pages (from-to)827-837
Number of pages11
JournalZeitschrift fur Physikalische Chemie
Issue number4
Publication statusPublished - 2017 Apr 1


  • ESR
  • high magnetic field
  • spin frustration
  • spinel
  • terahertz

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry


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