Nanoscale Transient Magnetization Gratings Created and Probed by Femtosecond Extreme Ultraviolet Pulses.

摘要: We utilize coherent femtosecond extreme ultraviolet (EUV) pulses from a free electron laser (FEL) to generate transient periodic magnetization patterns with periods as short 44 nm. Combining spatially excitation resonant probing at the M-edge of cobalt allows us create and probe gratings electronic magnetic excitations in CoGd alloy. In demagnetized sample, we observe an rise time close FEL pulse duration ∼0.5 ps decay indicative electron-phonon relaxation. When sample is magnetized saturation external field, grating, which appears on subpicosecond scale maxima EUV intensity then decays tens picoseconds via thermal diffusion. The described approach opens multiple avenues for studying dynamics ultrafast phenomena nanometer length scales.