Raman study of spin excitations in hexagonal RMnO3

• Speaker: Prof. Yang, In-Sang (Ewha Womans Univ)
• Date: Wednesday October 16, 2019 05:00pm
• Place: Jungho Seminar Room

Spin excitations in the Mn-ion plane in the hexagonal RMnO3 (R= Y, rare earths) manganite systems can be selectively probed by the resonance Raman technique. By choosing right resonance condition and appropriate polarization configuration, spin excitation scattering can be clearly observed, and the temperature dependence of the spin excitation scattering can be simple and powerful quantity for investigating spin-ordering as well as spin-reorientation transitions in RMnO3. Especially, the Raman method would be very helpful for investigating the weak spin-reorientation transitions by selectively probing the spin excitations in the Mn3+ ion sublattices, while leaving out the strong effects of paramagnetic moments of the rare earth ions. In this talk, I would like to review a short history of our studies on the spin excitations in hexagonal RMnO3 observed by Raman spectroscopy, an optical method. I hope that my talk stimulates the audience and that some of the audience return insights regarding the nature of the spin excitations which are rather high in energy (~0.1 eV) compared to usual magnons (~ a few meV) observed by neutron scattering.

1. Xiang-Bai Chen, Nguyen Thi Minh Hien, Kiok Han, Ji-Yeon Nam, Nguyen Thi Huyen, Seong-Il Shin, Xueyun Wang, S. W. Cheong, D. Lee, T. W. Noh, N. H. Sung, B. K. Cho, In-Sang Yang, Scientific Reports 5:13366, 2015.

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