Cr/Sc multilayers for the soft-x-ray range

Abstract

We have systematically investigated ultrathin Cr/Sc multilayers (nanolayers), using tunable soft-x-ray synchrotron radiation. The multilayers were optimized for use either in normal incidence or at 45 degrees at photon energies around the 2p-absorption edges of Sc (399 eV) and Cr (574 eV), respectively. They were sputter deposited on Si wafers or on thin Si(3)N(4)-membrane support structures for use in reflection and in transmission, respectively, as polarizing and phase-retarding elements in a polarimeter. The performance theoretically expected with respect to reflection/transmission and energy resolution has been confirmed experimentally: A value of 7% for the normal-incidence peak reflectance at 395 eV was measured as well as a pronounced minimum in transmission for certain incidence angles and energies below the respective absorption edges, indicating significant phase-shifting effects.