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We use time-resolved x-ray diffraction and magneto-optical Kerr effect to study the laser-induced antiferromagnetic to ferromagnetic phase transition in FeRh. The structural response is given by the nucleation of independent ferromagnetic domains (τ(1)~30 ps). This is significantly faster than the magnetic response (τ(2)~60 ps) given by the subsequent domain realignment. X-ray diffraction shows that the two phases coexist on short time scales and that the phase transition is limited by the speed of sound. A nucleation model describing both the structural and magnetic dynamics is presented.

We investigated the three-dimensional dynamics of the magnetization vector launched by an intense infrared pulse of femtosecond duration in a thin Fe film. We demonstrate how a single experiment of time-resolved magneto-optical Kerr effect can provide quantitative information on the temporal evolution of the magnetization trajectory. Our approach allows us to follow the precessional motion of the magnetization and to retrieve the modulus and orientation of the magnetocrystalline anisotropy field as a function of time—and therefore of the local temperature—providing a direct experimental evidence of the phenomenological mechanism triggering the magnetization precession

We report the results of time-and spin-resolved photoemission (TR-SPES) and time-resolved magneto-optical Kerr effect experiments on iron thin films. In particular, the extracted demagnetization times for both techniques are compared. It is shown that while for the Kerr measurements the demagnetization times are always limited by our time resolution (250 ± 30 fs), for the TR-SPES measurements this situation occurs only for relative quenching below 30%. Above this value, the measured TR-SPES demagnetization time exceeds 500 fs. Different demagnetization probes can hence track different demagnetization times.

A laser-based system for time-resolved photoemission spectroscopy using up to 6.2 eV photons is presented. The versatility of the laser source permits several combinations of pump and probe photon energies with pulse durations of 50-100 fs. The ultrahigh vacuum system, equipped with evaporators, a low energy electron diffraction system and an Auger spectrometer, grants the possibility to grow and characterize thin films in situ. The electron energy analyzer is a time-of-flight spectrometer with a multianode detector allowing high count rates. The performance of the whole experimental setup is investigated on Cu(100), Cu(111), and Ag(111) single crystals.