Structural disorder and electronic hybridization in NicMg1−cO solid solutions probed by XANES at the oxygen K edge

• Published in: Journal of physics. Condensed matter Vol. 19; no. 35; pp. 356219 - 356219 (11)
• Main Authors: Chen, Dongliang, Zhong, Jun, Chu, Wangsheng, Wu, Ziyu, Kuzmin, Alexei, Mironova-Ulmane, Nina, Marcelli, Augusto
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 05.09.2007; Institute of Physics
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron density of states and band structure of crystalline solids; Electron states; Exact sciences and technology; Other inorganic compounds; Physics; Nickel oxides; Fermi level; Solid solutions; XANES; Magnesium oxides; Chemical composition; Hybridization; Ionic radius; Electronic density of states; Multiple scattering
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/19/35/356219

A series of NicMg1-cO solid solutions has been studied for the first time looking at the structural disorder by means of x-ray absorption near-edge-structure (XANES) spectroscopy at the oxygen K edge. The experimental XANES signals were analysed within the full multiple scattering formalism and were interpreted taking into account clusters of up to 15 coordination shells around an absorbing oxygen atom. The substitution of nickel atoms by magnesium atoms results in a dramatic decrease of the empty density of states in the conduction band close to the Fermi level due to an exchange of the 3d(Ni)-2p(O) interaction with 3p(Mg)-2p(O). Besides, a simultaneous small decrease of the 3d(Ni)-2p(O) hybridization is also induced by the lattice expansion, determined by the difference in ionic radii between nickel and magnesium ions.