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Effect of high cobalt concentration on hopping motion in cobalt manganese spinel oxide (CoxMn3–xO4,x≥ 2.3)

Han, Hyuksu and Lee, Jae Seok and Ryu, Jeong Ho and Kim, Kang Min and Jones, Jacob L. and Lim, Jiun and Guillemet-Fritsch, Sophie and Lee, Han Chan and Mhin, Sungwook Effect of high cobalt concentration on hopping motion in cobalt manganese spinel oxide (CoxMn3–xO4,x≥ 2.3). (2016) Journal of Physical Chemistry C, 120 (25). 13667-13674. ISSN 1932-7447

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Official URL: http://dx.doi.org/10.1021/acs.jpcc.6b01440

Abstract

Hopping motions in cobalt manganese spinel oxides with high cobalt concentration (CoxMn3−xO4, 2.3 ≤ x ≤ 2.7) are investigated in order to clarify the origin of unusual electrical behaviors as negative temperature coefficient (NTC) thermistors. Based on the resistance versus temperature (R−T) characteristics, hopping conduction mechanisms in MCO compounds (x = 2.3 and 2.5) are attributed to variable range hopping (VRH) motion with a parabolic distribution of the density of states (DOS) near the Fermi level. However, when Co content increases up to 2.7, transition in the hopping motion occurs from VRH to the nearest neighboring hopping (NNH) motion, which can be responsible for a huge increase of the resistance accompanied by decrease of the factor of thermal sensitivity (B value) in MCO compounds (x = 2.7). Also, hopping distance and activation energies for MCO (x = 2.3 and 2.5) compounds following VRH conduction are calculated as a function of temperature, indicating that higher B value observed in MCO (x = 2.5) compound is due to the larger hopping distance compared to that of MCO (x = 2.3) compound.

Item Type:Article
Additional Information:Thanks to ACS editor. The original PDF of the article can be found at http://pubs.acs.org/doi/10.1021/acs.jpcc.6b01440
HAL Id:hal-01714097
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:Other partners > National Institute for Advanced Industrial Science and Technology - AIST (JAPAN)
French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Other partners > North Carolina State University (USA)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
Other partners > University of Florida (USA)
Other partners > Ajou University (KOREA)
Other partners > Korea Institute of Industrial Technology - KITECH (KOREA)
Other partners > Korea National University of Transportation - KNUT (KOREA)
Laboratory name:
Funders:
Business for Cooperative R&D
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Deposited By: cirimat webmestre
Deposited On:21 Feb 2018 10:35

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