Studies of magnetic materials by spectroscopy and diffractometry are developed further using high brilliant light sources at SPring-8. Polarization tunability of incident photons and polarization analysis of scattered X-rays are a promising item for studying electronic and magnetic structures in various magnetic materials. Feasibility of the diffractometer, installed on BL39XU for X-ray magnetic scattering and absorption experiments, is shown by recent results of X-ray magnetic circular dichroism, X-ray magnetic diffraction, and X-ray resonant magnetic scattering. For the experiments, phase retarder using a diamond single crystal plays an essential role for regulation of the polarization states and for recording the magnetic effects with high accuracy.
