Electrical, thermoelectrical and magnetic properties of approximately 20-nm Ni-Co-O nanoparticles and investigation of their conduction phenomena

Understanding the properties of semiconductor nanostructures is important for developing their practical applications in the nanodevices. Although the electrical properties of spinel oxides containing Ni and Co have been studied extensively over the last decades, there is still a significant disagre...

Full description

Saved in:
Bibliographic Details
Published in:Materials chemistry and physics 2017-05, Vol.192, p.41-47
Main Authors: Ibrahim, E.M.M., Abu-Dief, Ahmed M., Elshafaie, A., Ahmed, A.M.
Format: Article
Language:English
Subjects:
Antiferromagnetism
Cobalt oxides
Crystal lattices
Electrical conduction
Electrical properties
Fermi surfaces
Magnetic measurement
Magnetic properties
Nanoparticles
Nanostructured materials
Nanotechnology devices
Ni-Co oxide nanoparticles
Nickel oxides
Polarons
Power measurement
Semiconductors
Spinel
Spinel structure
Studies
Transition temperature
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Understanding the properties of semiconductor nanostructures is important for developing their practical applications in the nanodevices. Although the electrical properties of spinel oxides containing Ni and Co have been studied extensively over the last decades, there is still a significant disagreement on their electrical conduction mechanisms and the distribution of the various charge states of Co and Ni in the octahedral and tetrahedral sites of the spinel crystal lattice. In this study, Co3O4, NiO, and mixed Ni-Co oxide nanoparticles (NPs) of ∼20 nm are synthesized by co-precipitation method. The mechanism of the electrical conduction in the Co3O4 and Ni-Co oxides NPs is due to the hopping process in the octahedral site or between the octahedral and tetrahedral sites while in the NiO NPs, the large polarons conduction mechanism dominates. The thermoelectric power measurements confirm that the Ni-Co oxides NPs are non-degenerate semiconductors and the diffusion mechanism is the dominant component of the Seebeck coefficient. In contrast, the Co3O4 NPs show degenerate features with Fermi energy 0.054 eV. The NiO NPs exhibit a transition from non-degenerate to degenerate state. The magnetic measurements reveal an antiferromagnetic-paramagnetic transition at Néel transition temperature. The results are helpful to understanding the fundamental characteristics of the NPs under study. •Presents novel method for synthesis Ni-Co-O nanoparticles.•This article gives a significant understanding on the conduction mechanism of Ni-Co-O nanoparticles.•Present a novel comprehensive study on the type of carriers which governs the conduction mechanism.•The magnetic phase either antiferromagnetic or paramagnetic of all samples also has been studied.
ISSN:0254-0584
1879-3312
DOI:10.1016/j.matchemphys.2017.01.054