Time-resolved surface magnetometry in the nanosecond scale using synchrotron radiation

The dynamics of magnetization reversal at surfaces and interfaces is studied by a specific photoelectric effect experiment with pulsed soft x rays. This novel time-resolved surface magnetometry is based on the measure of the spin polarization of the total photoejected electron yield by means of a Mott scattering experiment and on the acquisition synchronism with the multibunch structure of the positron storage ring SuperAco at Orsay (500 ps pulses at 120 ns intervals). We present results on the fast magnetization reversal of Fe ultrathin films deposited on amorphous low-coercivity ferromagnetic ribbons.