1. Nonadiabatic small polarons, positive magnetoresistance, and ferrimagnetism behavior in the partially inverse Mn2-xV1+xO4 spinels.
- Author
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Pannunzio-Miner, E. V., De Paoli, J. M., Carbonio, R. E., and Sánchez, R. D.
- Subjects
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POLARONS , *MAGNETORESISTANCE , *FERRIMAGNETISM , *SPINEL group , *HIGH temperatures , *CATIONS , *MAGNETIC susceptibility - Abstract
We present experimental results of electrical resistivity (ρ), magnetoresistance (MR), Seebeck coefficient (S), and magnetic susceptibility (χ) experiments at high temperature on the spinel Mn2-xV1+xO4 series with x=0,
, and 1, prepared by solid state reaction. The Rietveld analysis of neutron powder diffraction (NPD) patterns confirm the expected cubic symmetry (SG: Fd-3m) with cell parameters around 8.5 Å. We also precisely calculate the distribution of Mn/V cations, in the tetrahedral and octahedral sites, for the whole series showing an important degree of inversion. The magnetic susceptibility and electrical transport properties show ferrimagnetic and semiconductor behaviors, respectively. A large difference detected between the activation energies for S and ρ indicates the presence of small polarons and the temperature dependence of ρ is well fitted with the nonadiabatic polarons model. All the samples present positive MR at room temperature, in particular, the highest value (around 1%) was observed in the MnV2O4 sample. [ABSTRACT FROM AUTHOR]1 3 - Published
- 2009
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