PHOTOINDUCED DEMAGNETIZATION AND ITS DYNAMICAL BEHAVIOR IN A (ND0.5SM0.5)(0.6)SR0.4MNO3 THIN-FILM

We have observed a significant change of absorption spectrum in the vi sible region by the irradiation of an intense laser pulse in a double- exchange ferromagnet (Nd0.5Sm0.5)(1-x)SrxMnO3 (x=0.4) thin film. In th e ferromagnetic state, the increase of spectral weight of the interban d transition between J-split bands has been observed, indicating that the photoexcited eg carriers suppress the neighboring spin correlation . The time-resolved spectroscopy in a vast time domain from 100 fs to 1 mu s has shown that the photoinduced demagnetization occurs within 2 00 ps after the photoinjection and spin correlation recovers in 300 ns . We further found that the demagnetization efficiency strongly depend s on the spin direction of the excited e(g) carriers.