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  Galakhov, V.R.; Udintseva, M.S.; Mesilov, V.V.; Gizhevskii, B.A.; Naumov, S.V.; Telegin, S.V.; Smirnov, D.A.: Milling-induced chemical decomposition of the surface of EuBaCo₂O_5.5 powders studied by means of soft X-ray absorption spectroscopy. Applied Surface Science 493 (2019), p. 1048-1054

10.1016/j.apsusc.2019.07.014

Abstract:
We present results of soft X-ray absorption spectroscopy studies of EuBaCo2O5.5 powders subjected to mechanical impact (milling in a ball mill). We show that in the near-surface region (5–10 nm) of particles of the powder, EuBaCo2O5.5 decomposes into Co3O4, BaCO3, and EuCoO3. A knowledge of the low-spin state of Co3+ ions in EuCoO3 and Co3O4 and possibilities of surface-sensitive soft X-ray absorption spectroscopy have allowed to determine the composition of the EuBaCo2O5.5 sample subjected to mechanical impact near its surface, which is inaccessible to standard X-ray phase analysis.