Single-phase spinel manganese cobalt oxides Mn 3Àx Co x O 4 dense ceramics were prepared for the first time and their structural/electrical property relationships characterized. The electrical properties, that is, the resistivity at 25°C, the energetic constant, and the resistance drift at 125°C, were determined and correlated with the cation distribution. Finally, the electrical characteristics of the Mn 3Àx Co x O 4 system were compare'd with other important classes of manganese-based spinel oxides, Mn 3Àx Ni x O 4 and Mn 3Àx Cu x O 4 , already commercialized as negative temperature coefficient (NTC) thermistors. The high values of energetic constant and low resistivities observed in Mn 3Àx Co x O 4 ceramics present a promising interest for such industrial applications. *tenailleau@chimie.ups-tlse.fr

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