NI K-EDGE XANES STUDIES OF HOLE-DOPED ND2-XSRXNIO4 AND REDUCED ND2-XSRXNIOY

In the present work we have analyzed the Ni K-edge XANES of two series of families in order to determine their Ni oxidation state: i) the ho le doped Nd2-xSrxNiO4 (0.2 dagger x dagger 0.8); and ii) the reduced N d(2-x)Sr(x)NiOy (0.2 dagger x dagger 0.5 and 3.5 dagger y dagger 3.79) . The Ni K-edge XANES shows an increase of Ni(III) content with the Sr concentration for the hole doped samples. Additionally, the reduced f amily shows the disappearance of NI(III), a decrease of Ni(II) with re spect to the non-reduced one and an increase of Ni(I).