Ultrafast photoinduced magnetic moment in a charge-orbital-ordered antiferromagnetic Nd0.5Sr0.5MnO3 thin film

The effect of photoexcitation in the charge sector on the magnetization has been studied with subpicosecond optical pump-and-probe measurements in an antiferromagnetic manganite. Magneto-optic Kerr measurements show a steplike increase of magnetic moment followed by a gradual growth. The steplike behavior is ascribed to the spin flip scattering in the excited states while the slower process to the spin-lattice thermalization, which exhibits slowing down toward the antiferromagnetic-ferromagnetic transition temperature. The time scale of these processes is much faster compared to the photoinduced demagnetization time of ferromagnetic manganites and reflects the effect of underlying spin-charge-orbital order.