Structural and transport properties of Mg1-xMnxMn2O4 +/-delta spinels

摘要

The synthesis and structural properties of Mg1-xMn2+xO4, for 0 less than or equal to x less than or equal to 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 600degreesC the inversion degree (m) starts increasing. The electrical conductivity shows a small dependence On P(O-2) 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. (C) 2002 Elsevier Science (USA). [References: 16]