[9p-Z23-1~11] 4.6 Terahertz Photonics

▲ [9p-Z23-3] Terahertz Time-Domain Magneto-spectroscopy of LaMnO₃ and La_0.875Sr_0.125MnO₃

〇(D)Fuyang Tay¹, Nicolas Marquez Peraca¹, Xinwei Li², Jiaming He³, Andrey Baydin¹, Jianshi Zhou³, Junichiro Kono¹ (1.Rice Univ., 2.California Inst. of Tech., 3.Univ. of Texas at Austin)

Keywords:THz time-domain magneto-spectroscopy, perovskite manganite, colossal magnetoresistance

Doped perovskite manganites (e.g., La_1-xSr_xMnO₃ or LSMO) have attracted considerable interest over the last few decades due to their complex phase diagrams and the discovery of the colossal magnetoresistance (CMR) effect. To date, the origin of the CMR effect and some unusual states, for instance, the ferromagnetic insulator (FI) phase in La_0.875Sr_0.125MnO₃ at low temperatures, are still not well understood. It is challenging to extract the full picture from time-integrated spectroscopy measurements due to the strong interplay among the charge, spin, orbital, and lattice degrees of freedom in the manganites. Ultrafast pump-probe spectroscopy has been suggested as a powerful tool for providing insight into such complex materials by investigating their dynamics after optical excitation. Terahertz (THz) spectroscopy is particularly important to probe low-energy collective excitations such as phonons, magnons, and charge density wave (CDW) condensate. Here, we studied the temperature and magnetic field dependence of THz transmission in LaMnO₃ (LMO) and LSMO (x = 0.125) single crystals. The optical conductivity spectra showed basic agreement with expectations based on the known phase diagram but revealed new resonance modes in the THz regime in both crystals. Future work will include optical-pump/THz-probe experiments of both crystals to study light-induced phase transitions.