Electron spin resonance study of Cu benzoate using a 3He-4He dilution refrigerator

Takuo Sakon, Hiroyuki Nojiri, Keiichi Koyama, Takayuki Asano, Yoshitami Ajiro, Mitsuhiro Motokawa

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9 Citations (Scopus)


An electron spin resonance (ESR) measurement system for use at ultralow temperatures using a 3He-4He dilution refrigerator has been developed. As the first experiment, the ESR was measured on a quantum spin chain Cu benzoate down to 160 mK, in which a field-induced gap was recently found.4) The evaluation of a new ESR mode, the so-called breather mode, was found at the lowest temperatures. In the previous ESR down to 0.5 K, this mode was clearly found for H ∥ c, in which the magnitude of the gap is largest. In the present work, the achievement of low temperatures enabled us to observe a smaller gap in H ∥ b by suppressing the thermal excitation. The magnitude of the field-induced gap evaluated from the nonlinear field dependence of the mode shows good agreement with that determined by previous specific heat measurements.

Original languageEnglish
Pages (from-to)2259-2262
Number of pages4
JournalJournal of the Physical Society of Japan
Issue number8
Publication statusPublished - 2001 Aug 1


  • Cu benzoate
  • Electron spin resonance
  • Quantum spin system
  • Ultralow temperatures

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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