Физика Низких Температур: Том 31, Выпуск 8-9 (Август 2005), c. 1024-1031    ( к оглавлению , назад )

Direct optical excitation of two and three magnons in a-Fe2O3

Y. Tanabe1, Y. Fujimaki2, K. Kojima2, S. Uchida2, S. Onari3, T. Matsuo3, S. Azuma4, and E. Hanamura4

1Department of Applied Physics, University of Tokyo, 7–3–1 Hongo, Tokyo 113–8656, Japan

2Department of Physics, University of Tokyo, 7–3–1 Hongo, Tokyo 113–8656, Japan

3Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 304–8573, Japan

4Chitose Institute of Science and Technology and Japan Science and Technology Agency Chitose, Hokkaido 066-8655, Japan
E-mail: hanamura@photon.chitose.ac.jp

Received December 20, 2004

Аннотация

Direct excitation of two and three magnons is observed in midinfrared absorption and Raman scattering spectra of a-Fe2O3 crystals. These polarization characteristics and the spectra themselves are shown to be understood from group-theoretical point of view. The microscopic mechanism of three-magnon excitation is proposed in addition to that of well-known two-magnon excitation process.

PACS:
75.30.Ds - Spin waves (for spin-wave resonance, see 76.50.+g)
78.30.-j - Infrared and Raman spectra (for vibrational states in crystals and disordered systems, see 63.20.-e and 63.50.+x respectively)
75.50.Ee - Antiferromagnetics