Integrated magnetic spectroscopy of dilute magnetic semiconductors (invited)

An integrated dc SQUID magnetic spectrometer has been developed to obtain direct high-resolution measurements of optically induced magnetization in a 10-μm-diam sample of Cd0.8Mn0.2Te. The static and picosecond dynamics of the magnetic response have been studied and are seen to be strikingly dependent on the energy and polarization of the optical excitation. The entire sample magnetization changes upon illumination, and the disturbed spins relax via an efficient spin coupling to the lattice.