XPS Valence Band Studies of LaNi5-xMx (M = Al, Co; x =0, 1) Alloy Thin Films
J. Skorynaa, A. Marczyńska a, S. Pacanowski b, A. Szajek a and L. Smardz a
aInstitute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland
bFaculty of Technical Physics, Poznań University of Technology, Piotrowo 3, 60-965 Poznań, Poland
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LaNi5-xMx (M = Al, Co) alloy thin films were prepared onto oxidised Si(100) substrates in the temperature range of 285-700 K using UHV magnetron co-sputtering. The surface chemical composition and valence bands of all the alloy thin films were measured in situ, immediately after deposition, transferring the samples to an UHV analysis chamber equipped with X-ray photoelectron spectroscopy. Results showed that the shape of the valence bands measured for the polycrystalline samples is practically the same compared to those obtained theoretically from ab initio band structure calculations. On the other hand, the X-ray photoelectron spectroscopy valence bands of the nanocrystalline thin films (especially LaNi4Co) are considerably broader compared to those measured for the polycrystalline samples. This is probably due to a strong deformation of the nanocrystals. Therefore, the different microstructure observed in polycrystalline and nanocrystalline alloy thin films leads to significant modifications of their electronic structure.

DOI: 10.12693/APhysPolA.127.430
PACS numbers: 73.22.-f, 71.20.-b