  A novel design of high-voltage compatible polarimeter for spin-resolved hard
x-ray photoelectron spectroscopy (Spin-HAXPES) went into operation at beamline
BL09XU of SPring-8 in Hyogo, Japan. The detector is based on the
well-established principle of electron diffraction from a W(001) single-crystal
at a scattering energy of 103.5 eV. Its special feature is that it can be
operated at a high negative bias potential up to 10 kV, necessary to access the
HAXPES range. The polarimeter is operated behind a large hemispherical analyzer
(Scienta R-4000). It was optimized for high transmission of the transfer
optics. The exit plane of the analyzer contains a delay-line detector (20 mm
dia.) for conventional multichannel intensity spectroscopy simultaneously with
single-channel spin analysis. The performance of the combined setup is
demonstrated by the first spin-resolved data for the valence-region of a FeCo
functional layer of a tunneling device, buried beneath 3 nm of oxidic material.
The well-structured spin polarization spectrum validates Spin-HAXPES in the
valence energy range as powerful method for bulk electronic structure analysis.
The spin polarization spectrum exhibits a rich structure, originating from
clearly discernible transitions in the majority and minority partial spin
spectra.
