The X-ray photoelectron spectroscopy and high-temperature structural studies of Zn1-xNixO/NiO two-phase composites

Joshi, DC and Nayak, S and Suresh, P and Suresh, KS and Kumar, Manoj BV and Thota, S (2015) The X-ray photoelectron spectroscopy and high-temperature structural studies of Zn1-xNixO/NiO two-phase composites. In: PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, 252 (10). pp. 2323-2329.

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Abstract

Detailed investigation of the chemical states and local atomic environment of Ni and Zn in the two-phase composites of Zn1-xNixO/NiO was reported. The X-ray photoelectron spectra of both Ni-2p and Zn-2p revealed the existence of a doublet with spin-orbit splitting approximate to 17.9 and 23.2eV, respectively confirming the divalent oxidation state of both Ni and Zn. However, the samples fabricated under oxygen-rich conditions exhibit significant difference in the binding energy approximate to 18.75eV between the 2p3/2 and 2p1/2 states of Ni. The shift in the satellite peaks of Ni-2p with increasing the Ni composition x within the Zn1-xNixO/NiO matrix signifies the attenuation of nonlocal screening because of reduced site occupancy of two adjacent Zn ions. The temperature dependence of X-ray diffraction analysis reveals a large distortion in the axial-rhombohedral angle for oxygen-rich NiO. Conversely, no significant distortion was noticed in the NiO system present as a secondary phase within Zn1-xNixO. Nevertheless, the unit-cell volume of both wurtzite h.c.p. Zn1-xNixO and f.c.c. NiO exhibits an anomalous behavior between 150 and 300 degrees C. The origin of such unusual change in the unit-cell volume was discussed in terms of oxygen stoichiometry.

Item Type:	Journal Article
Publication:	PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
Publisher:	WILEY-V C H VERLAG GMBH
Additional Information:	Copy right for this article belongs to the Indian Inst Sci, Dept Phys, Bangalore 560012, Karnataka, India
Keywords:	Neel temperature; NiO; Rhombohedral distortions; spin-orbit coupling; X-ray photoelectron spectroscopy; Zn1-xNixO
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	05 Nov 2015 07:21
Last Modified:	05 Nov 2015 07:21
URI:	http://eprints.iisc.ac.in/id/eprint/52687

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