Mapping of unoccupied minority spin bands of Co and Ni using inverse photoemission

Abstract

Angle-resolved inverse photoemission (or bremsstrahlung spectroscopy) with a tunable light detector is used to determine the energy-band dispersion of unoccupied minority-spin $3d$ states in Co and Ni. For Co, a ferromagnetic exchange splitting of 0.93 \ifmmode\pm\else\textpm\fi{} 0.1 eV between the unoccupied spin-down and occupied spin-up states (measured with photoemission) is derived. The full width at half maxiumum of empty $3d$ states in Ni is 0.25 \ifmmode\pm\else\textpm\fi{} 0.1 eV.