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Int. J. Electroactive Mater. 6 (2018) 14-20

Study of DC conductivity in nanostructured ceramics of NiMn2O4 pure and doped with Cu and Zn

Victor Alves Soares*, Marcelo Souza da Silva

Departamento de Física do IF SertãoPE campus Salgueiro, Instituto Federal do Sertão Pernambucano, Salgueiro, Pernambuco, Brazil
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Abstract : In this paper we present the structural, DC electrical characterization of ceramics based on nickel manganite (NiMn2O4, NMO) pure and doped with 5 mole % of Cu2+, and Zn2+ produced by the sol-gel method. The ceramic bodies of nickel manganite were sintered at a temperature of 1000 °C during 3 h. The structural characterization was based on the techniques of the scanning electron microscopy (SEM), X-ray diffraction (XRD). The resistivity was studied using temperature dependent resistance measurements (TDR). This work aims to produce and characterize nickel manganite ceramics obtained by nanopowders with a single cubic phase synthesized using the sol-gel method. It will study the influence on the microstructure and the electrical conductivity of the addition of transition metals such as Zn 2+ and Cu 2+, a novelty for this system. The crystallite size and particle size, respectively obtained by XRD and SEM, were of around 50 nm and 0.7 μm. The pure samples showed NTCR behavior, but the addition of the dopant allows reducing the activation energy by making them semiconductor, resulting in many different resistivity values at room temperature.

Keywords : Sol-gel method,NTC,spinel