Electronic structures of AgNi1-xCoxO2 delafossite oxides

Abstract: Electronic structures of delafossite oxides have been investigated by using photoemission spectroscopy (PES) and soft X-ray absorption spectroscopy (XAS). T 2p XAS (, Ni) spectra of show that the valence states of Co ions are trivalent and do not change with . In contrast, Ni ions are in the mixed-valent states and the trivalent component increases with increasing . This finding suggests that the metallic nature of for low values of arises from the divalent Ni ions. The valence-band PES study of reveals that the Ni 3d states are more metallic like than the Co 3d states. [Copyright &y& Elsevier]