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キーワード:
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要旨:
The magnitude of the spin polarization at the Fermi level of
ferromagnetic materials at room temperature is a key property for
spintronics. Investigating the Heusler compound Co2MnSi, a value of 93%
for the spin polarization has been observed at room temperature, where
the high spin polarization is related to a stable surface resonance in
the majority band extending deep into the bulk. In particular, we
identified in our spectroscopical analysis that this surface resonance
is embedded in the bulk continuum with a strong coupling to the majority
bulk states. The resonance behaves very bulklike, as it extends over the
first six atomic layers of the corresponding (001) surface. Our study
includes experimental investigations, where the bulk electronic
structure as well as surface-related features have been investigated
using spin-resolved photoelectron spectroscopy (SR-UPS) and for a larger
probing depth spin-integrated high energy x-ray photoemission
spectroscopy (HAXPES). The results are interpreted in comparison with
first-principles band structure and photoemission calculations which
consider all relativistic, surface, and high-energy effects properly.
