Magnetic phase transition in DyFe0.6Mn0.4O3 crystal investigated
By use of optical pump-probe spectroscopy, we report the ultrafast carrier dynamics in a DyFe0.6Mn0.4O3 (DFMO) single crystal. We find that the photo-excited electrons firstly relax through a fast electron-phonon coupling , followed by intermediate relaxation (tens of ps) and slow nanosecond relaxation processes. Meanwhile, a photo-induced coherent acoustic phonon with frequency of 36.3 GHz is detected, and the sound velocity with magnitude of 2.65 x 103 m/s is determined. Moreover, the time constants in intermediate relaxation are found to increase significantly in the vicinity of the Morin-like phase transition temperature and the Néel temperature, which are interpreted as the coexisting of collinear- and canted-antiferromagnetic properties in DFMO, and the spectroscopic results are consistent with the temperature-dependent magnetic-moment measurements.