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Journal of Materials Science

, Volume 30, Issue 7, pp 1845–1848 | Cite as

Preparation and electrical properties of monophase cubic spinel, Mn1.5Co0.95Ni0.55O4, derived from rock salt type oxide

  • T. Yokoyama
  • K. Kondou
  • K. Komeya
  • T. Meguro
  • Y. Abe
  • T. Sasamoto
Papers

Abstract

The purpose of this study was to prepare a sintered body consisting of monophase cubic spinel type oxide, Mn1.5Co0.95Ni0.55O4, and to evaluate its electrical properties. It was found that cooling from 1400 to 1000 °C in nitrogen did not affect the preservation of the sintered rock salt type oxide formed at 1400 °C. A crack free sintered body of monophase cubic spinel may be obtained by heat treatment at 1000 °C in air, using a specimen cooled from 1400 °C at a rate of 500 °C min −1. A heat treatment time in air at 1000 °C of more than 48 h was required to convert the rock salt type structure into a perfect cubic spinel structure. The electrical conductivity, δ, of the sintered cubic spinel oxide synthesized in this work was found to be stable at 100 and 200 °C in air and at 100, 200 and 300 °C in nitrogen. The sintered spinel oxide was a p-type semiconductor, based on small polaron hopping conduction. The intrinsic hole concentration, n, was estimated to be constant, with a value of 1.6–1.8×1028m−3. The mobility, μ, increased exponentially with increasing annealing temperature in both atmospheres, suggesting that the change in δ is dependent on μ.

Keywords

Heat Treatment Electrical Conductivity Electrical Property Spinel Structure Hole Concentration 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Chapman & Hall 1995

Authors and Affiliations

  • T. Yokoyama
    • 1
  • K. Kondou
    • 1
  • K. Komeya
    • 1
  • T. Meguro
    • 1
  • Y. Abe
    • 2
  • T. Sasamoto
    • 3
  1. 1.Yokohama National UniversityYokohama-shiJapan
  2. 2.Technol Seven Co., LtdYokohama-shiJapan
  3. 3.Kanagawa Institute of TechnologyAtsugi-shiJapan

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