3 documents found, page 1 of 1
Synthesis and electrical properties of nanocrystalline Ca1−xEuxMnO3±δ
Lopes, ME; Silveira, C; Nunes, M R; Melo Jorge, M ENanopowders of Ca1−xEuxMnO3 (0.1≤x≤0.4) manganites were synthesized as a single phase using the auto gel-combustion method. The citrate method shows to be simple and appropriate to obtain single phases avoiding segregation or contamination. The Ca1−xEuxMnO3 system has been synthesized at 800 °C during 18 h, against the conventional method of mixing oxides used to obtain these materials at higher temperatures of...
Low-temperaturesynthesisofnanocrystalline Ca1 xHoxMnO3 d (0pxp0.3) powders
Lopes, M E; Isasi, P H; Nunes, M R; Melo Jorge, M ENanocrystalline Ca1 xHoxMnO3 d (0<x<0.3)manganites were synthesized as phase-pure by a simple and instantaneous solution autogel combustion method,which is a low temperature initiated synthetic route to obtain fine grain size. All the samples,heated at 800 ºC for 18h,can be produced as phase-pure; the polycrystalline powders are homogeneous and possess ultrafineparticle size.The holmium-doped calcium manganites...
Properties of Ca1−xHoxMnO3 perovskite-type electrodes
Ferreira, B M; Melo Jorge, M E; Lopes, M E; Nunes, M R; Silva Pereira, M IIn this work, Ca1−xHoxMnO3 (x = 0, 0.1 and 0.2) perovskite oxide pelleted electrodes were prepared from the respective powders obtained by the citrate route method at 1173 K. The electrodes exhibit particle size that decreases with the holmium content in the oxide. All the samples reveal semiconductor behaviour and the presence of holmium induces a marked decrease in the electrical resistivity. The results can ...