Spin-lattice relaxation phenomena in manganite La0.7Sr0.3MnO3 thin films

Time-resolved magneto-optics was used to study spin-lattice relaxation dynamics in thin epitaxial La0.7Sr0.3MnO3 films. Two distinct recovery regimes of the ferromagnetic order can be resolved upon photoexcitation, which manifest themselves by two different relaxation times. A pump pulse energy-independent spin-lattice relaxation time can be deduced. Due to a weak spin-orbit coupling in manganites this spin-lattice relaxation time is much longer than in ferromagnetic metals. Heat flow into the substrate sets the ultimate recovery speed of the ferromagnetic order and allows for a determination of heat diffusion properties of manganite films.