Structural and Transport Properties of Mg1−xMnxMn2O4±δ Spinels

• Published in: Journal of solid state chemistry 2002-06, Vol.166 (1), p.171-176
• Main Authors: Malavasi, Lorenzo, Ghigna, Paolo, Chiodelli, Gaetano, Maggi, Giorgio, Flor, Giorgio
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Conductivity phenomena in semiconductors and insulators; electrical conductivity; Electronic transport in condensed matter; Exact sciences and technology; Inorganic compounds; inversion; Low-field transport and mobility; piezoresistance; MgMn2O4 spinel; Physics; Salts; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Thermoelectric and thermomagnetic effects; X-ray diffraction
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1006/jssc.2002.9577

The synthesis and structural properties of Mg1−xMn2+xO4, for 0≤x≤1 are described. Complete miscibility in the solid state exists for this system. For the material with the correct stoichiometry, i.e. MgMn2O4, the effect of temperature on the cation distribution was investigated= above 600°C the inversion degree (m) starts increasing. The electrical conductivity shows a small dependence on P(O2) which is consistent with the small oxygen non-stoichiometry determined by means of thermogravimetry. The main contribution to the transport properties arises from the inversion equilibrium. Two distinct conductivity regimes, below and above the inversion threshold, can be assumed to explain the electrical conductivity and thermoelectric power results.