日本原子力研究開発機構 (JAEA) / 量子ビーム応用研究部門
放射光科学研究ユニット / 放射光量子シミュレーショングループ
|日時:||平成19年 7月5日(木) 16：00〜|
|Date and time:||5th July (Thu.) 16:00〜|
|Place:||SPring-8, "HOUKOUKAN" seminar room|
|Title:||Electron Spin Resonance Intensity in Spin Dimer Systems|
|講演者:||松本正茂 氏 (静岡大学理学部物理)|
|Speaker:||Prof. Masashige Matsumoto (Shizuoka University)|
Electron spin resonance (ESR) is one of the most important experiments to study magnetic excitations. The development in high magnetic field experiments enables us to study magnetic field-induced ordering in quantum spin systems. Here we discuss interacting spin dimers [1,2]. The groundstate of TlCuCl3 is a spin-singlet liquid with only short-range correlations. The triplet excitations require a finite excitation energy from the spin-singlet groundstate. ESR experiments were performed in TlCuCl3 and KCuCl3 to reveal field dependence of magnetic excitations [3,4]. They observed transitions from the groundstate to excited states in both disordered and ordered phases. Sakai et al. studied the direct ESR transition theoretically taking Dzyaloshinskii-Moriya interactions into account . We extend this type of study and investigate ESR intensity in both disordered and ordered phases applying a spin-wave theory described by bond operators, and elucidate effects of the Dzyaloshinskii-Moriya interaction on the ESR transition.
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