Quantum-beat FID and spin cross relaxation in the ground state of magnetic ions in aqueous solutions

Summary form only given. In the study on fast spin dynamics in condensed matter near room temperature, optical pumping with a short laser pulse is very useful. The observations of the spin relaxation and the free-induction-decay signal in the nanosecond region have been reported, where the time derivative of the optically-induced magnetization was monitored by a pickup coil. However, the resolution time of the detection system in such experiments is of the order of 1 ns at best. In order to study ultrafast spin dynamics in the picosecond and femtosecond regions, we apply the polarization spectroscopy with the pump-probe technique to the creation and detection of the magnetization. In the present work, we report on the fast spin dynamics in aqueous solutions of transition-metal ions at room temperature.