セミナー情報

第27回 原研・兵県大合同コロキウム

日時: 平成19年 7月5日(木) 16：00〜
Date and time: 5th July (Thu.) 16:00〜
場所: SPring-8, 萌光館
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)
Abstract:

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 [5]. 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.

[1] A. Oosawa, M. Ishii and H. Tanaka, J. Phys.: Condens. Matter 265 (1999).

[2] T. Nikuni, M. Oshikawa, A. Oosawa and H. Tanaka, Phys. Rev. Lett. 84, 5868 (2000).

[3] H. Tanaka, T. Takatsu, W. Shiramura, T. Kambe, H. Nojiri, T. Yamada, S. Okubo, H. Ohta and M. Motokawa, Physica B 246-247, 545 (1998).

[4] V. N. Glazkov, A. I. Smirnov, H. Tanaka and A. Oosawa, Phys. Rev. B 69, 184410 (2004).

[5] T. Sakai, O. Cépas and T. Ziman, J. Phys. Soc. Jpn. 69, 3521 (2000).