Ultrafast thermoelastic dynamics of HoMnO₃single crystals derived from femtosecond optical pump–probe spectroscopy

Abstract

In this paper, the photo-induced ultrafast thermoelastic dynamics of hexagonal HoMnO3 single crystals has been studied by using optical pump–probe spectroscopy. The thermoelastic effect in the ab-plane of hexagonal HoMnO3, associated with giant magnetoelastic coupling around the Néel temperature (TN), is intimately correlated to the emergence of a negative component in the transient reflectivity changes (ΔR/R) obtained in temperature-dependent pump–probe experiments. Moreover, the variation in the oscillation period in ΔR/R caused by a strain pulse propagating along the c-axis exhibits an abrupt drop around TN, presumably due to the antiferromagnetic-ordering-induced changes in ferroelectricity.