Ultrafast thermoelastic dynamics of HoMnO3 single 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 Neel temperature (T-N), is intimately correlated to the emergence of a negative component in the transient reflectivity changes (Delta R/R) obtained in temperature-dependent pump-probe experiments. Moreover, the variation in the oscillation period in Delta R/R caused by a strain pulse propagating along the c-axis exhibits an abrupt drop around T-N, presumably due to the antiferromagnetic-ordering-induced changes in ferroelectricity.