Effect of nanoparticles agglomeration on electrical properties of La1−xAxMnO3 (A = Sr, Ba) nanopowder and ceramic solid solutions

Peculiar features of the sol–gel synthesis of substituted manganites La1−xAxMnO3 (A = Sr, Ba) have been investigated. Variation of the gel pH during synthesis was shown to affect the aggregation of particles and their crystal structure. Electrical properties of nanopowder and ceramic La1−xAxMnO3 solid solutions were studied. Additional heat treatment was revealed to affect not only the resistivity, but also the character of its temperature dependence. It was shown that under the synthesis and heat treatment conditions used in the work, the La1−xBaxMnO3 solid solutions with x = 0.15 have the lowest conductivity at 1200 K, which allows using them as thick-film cathodes.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Peculiarities of sol–gel synthesis of substituted Sr, Ba manganites as cathodes. ► Gel pH during synthesis affects aggregation and crystal structure of particles. ► At high temperatures conductivity arises due to hopping of small polarons. ► Additional heat treatment of ceramics affects temperature dependence of resistivity. ► Low-resistance samples synthesized which convenient for thick-film cathodes.