Spectroscopy of the electronic states of the Heusler compounds Co2FeAl and Co2Cr0.6Fe0.4Al and the influence of oxidation

Martin Jourdan (1) , Fabian Grosse-Schulte (1) , Michaela Hahn (1) , Gerd Schönhense (1)

1 Institut für Physik [Mainz]

The band structures of the Heusler compounds Co 2 Cr 0.6 Fe 0.4 Al and Co 2 FeAl were investigated in-situ by angle resolved ultraviolet photoemission spectroscopy (ARUPS). The samples were prepared by a sputtering process optimized for tunneling junction preparation, the photoemission process in normal direction of the (001)-oriented thin films was excited by a Helium gas discharge lamp (hν = 21.2eV and hν = 40.8eV). The spectra of clean samples are compared with calculations of the total and partial bulk density of states and are evaluated within the three-step model of photoemission. Basic agreement with theoretical predictions of the bulk band structure is concluded. At oxygen exposures of the thin films of only 1 Langmuir a chemisorption phase with significant changes of the valence-band spectrum near the Fermi-energy is observed. At 10L oxygen the spectra are indicative of an oxide within the UPS probing depth.

Mots clés: Physical Sciences

Martin Jourdan, Fabian Grosse-Schulte, Michaela Hahn, Gerd Schönhense. Spectroscopy of the electronic states of the Heusler compounds Co2FeAl and Co2Cr0.6Fe0.4Al and the influence of oxidation. Journal of Physics D: Applied Physics, 2011, 44 (15), pp.155001. ⟨10.1088/0022-3727/44/15/155001⟩. ⟨hal-00609757⟩