Faculté des sciences

Photoemission with high angular and energy resolution: Temperature dependent exchange splitting in nickel

Kreutz, T. J. ; Aebi, Philipp ; Osterwalder, Jürg

In: Solid State Communications, 1995, vol. 96, no. 6, p. 339-343

Ultraviolet photoemission spectroscopy data from a Ni(110) crystal taken with high angular and energy resolution at room temperature (RT) and near the ferromagnetic Curie temperature are presented. For a polar scan in the (001) plane we recorded energy spectra within 1.5 eV from the Fermi energy (EF) in 1° steps. Distinct bands crossing EF can be well separated and, by... More

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    Summary
    Ultraviolet photoemission spectroscopy data from a Ni(110) crystal taken with high angular and energy resolution at room temperature (RT) and near the ferromagnetic Curie temperature are presented. For a polar scan in the (001) plane we recorded energy spectra within 1.5 eV from the Fermi energy (EF) in 1° steps. Distinct bands crossing EF can be well separated and, by comparing the RT data with a recent band structure calculation [H. Eckardt, L. Fritsche, J. Phys. F17, 925 (1987)], the bands can be assigned to a minority d-band and two exchange split sp-bands. While their exchange splitting can hardly be extracted from the energy spectra, the peaks are well separated in k-space, i.e., in polar angle. We determine ΔEex = 204±8 meV for the sp-band in the examined k-region and find that the angular line width of the majority sp-band is significantly smaller than that of the minority sp-band. Upon approaching TC the exchange splitting of the sp-band vanishes and the d-band becomes very broad.