TY - JOUR
T1 - Electron spin resonance study of Cu benzoate using a 3He-4He dilution refrigerator
AU - Sakon, Takuo
AU - Nojiri, Hiroyuki
AU - Koyama, Keiichi
AU - Asano, Takayuki
AU - Ajiro, Yoshitami
AU - Motokawa, Mitsuhiro
PY - 2001/8/1
Y1 - 2001/8/1
N2 - 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.
AB - 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.
KW - Cu benzoate
KW - Electron spin resonance
KW - Quantum spin system
KW - Ultralow temperatures
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U2 - 10.1143/JPSJ.70.2259
DO - 10.1143/JPSJ.70.2259
M3 - Article
AN - SCOPUS:0035600559
VL - 70
SP - 2259
EP - 2262
JO - Journal of the Physical Society of Japan
JF - Journal of the Physical Society of Japan
SN - 0031-9015
IS - 8
ER -