Low Temperature Physics: 28, 480 (2002); https://doi.org/10.1063/1.1496656 (11 pages)
Физика Низких Температур: Том 28, Выпуск 7 (Июль 2002), c. 677-690    ( к оглавлению , назад )

Recent progress in magneto-optics and research on its application

Norimichi Kojima

Graduate School of Arts and Sciences, The University of Komaba 3-8-1, Meguro-ku, Tokyo 153-8902, Japan
E-mail: cnori@mail.ecc.u-tokyo.ac.jp

Kuniro Tsushima

Kyushu Institute of Information Sciences, saifu 6-3-1, Dazaifu, Fukuoka 818-0117, Japan

Received April 10, 2002


We have investigated various kinds of magneto-optical properties for rare earth orthochromites. In RCrO3(R = Tb, Dy and Ho), from the analysis of Cr3+ exciton absorption, it was elucidated that these compounds exhibit an anomalous spin-reorientation under the magnetic field along the b axis, where the weak ferromagnetic moment of the Cr3+ spins rotates in the ac plane perpendicular to the b axis. In these compounds, when the R3+ spin configuration is disordered, an anomalous satellite band appears in the lower energy side of the Cr3+ exciton absorption, which is associated with the breakdown of k = 0 selection rule caused by the disorder of R3+ spin configuration. In YbCrO3, various kinds of cooperative excitations such as Cr3+ exciton coupled with Yb3+ magnon and Cr3+-Yb3+ exciton molecule appear in the visible region, which are induced by the antisymmetric exchange interaction between the Cr3+ and Yb3+ spins. The propagation of these cooperative excitations strongly depends on the spin structure and the external magnetic field. In ErCrO3, a photo-induced spin-reorientation takes place within 50 ms after the photo-irradiation corresponding to the 4A2g ®2Eg transition of Cr3+, and it returns to the initial spin configuration in about 400 ms. This phenomenon was detected by the time-resolved Er3+ absorption spectra corresponding to the 4I15/2®4I9/2 transition. Finally, we briefly review the recent frontier research on application mainly developed in Japan.

78.20.Ls - Magnetooptical effects