The magnetic properties and electrical conduction mechanism of Co1-xMnxFe2O4 spinel

Co1-xMnxFe2O4 spinels were synthesized at 1080 degrees C in air as bulk phases. The lattice parameters increase with the addition of Mn cation, which is closely related to the effective substitution of Mn2+ cation. From the measurements of the magnetic moment, it is shown that Mn contributes to the canted magnetic moment between tetrahedral (A) and octahedral (B) sites, except for the sample with x = 0.2. The n-type conduction was observed from Seebeck coefficient measurements: this is ascribed the formation of Co3+ + e(-) and Mn3+ + e(-) from Co2+ and Mn2+ cations on A and B sites. The electrical conductivities increase with Mn substitution. It is suggested that the possibility of charge transfer between 2+ and 3+ cation in A as well as B sites may contribute to electrical conductivity. (C) 1998 Elsevier Science S.A. All rights reserved.