Faraday effect and x-ray birefringence at cobalt K-absorption edge with the tunable x-ray polarimeter

We have measured the Faraday effect of cobalt polycrystalline foil near cobalt K-absorption edge with the energy-tunable x-ray polarimeter. The Kramers-Kronig (K-K) relation between spectrum of the Faraday rotation and magnetic circular dichroism measured by using the ellipticity polarized synchrotron x-radiation has been confirmed. Furthermore, we have constructed, a new type of x-ray polarimeter with a diamond phase retarder and measured x-ray linear dichroism (LD) and linear birefringence (LB) simultaneously using an hcp cobalt single crystal foil. The K-K relation between LD and LB has also been confirmed clearly.