Dependence of structural/morphological and magnetic properties of LaCoO${}_3$ nanoparticles prepared by citrate nitrate auto combustion

Perovskite LaCoO${}_3$ nanopowders were synthesized via solution auto-combustion chemical route, using lanthanum and cobalt nitrates as oxidants and citric acid as fuel. Qualitative and Quantitative phase analysis performed by Rietveld refinements indicated the presence of pure single LaCoO${}_3$ phase. From fit parameters, goodness of fit "S" parameter (close to 1) and the difference between the experimental and theoretical XRD patterns. FTIR spectra showed two characteristics bands at 408 and 589 cm${}^{-1}$ characteristics of metal oxygen bands vibration, thus confirming the formation of LaCoO${}_3$ phase, whereas the strong absorption band at 589 cm${}^{-1}$ was assigned to Co–O stretching vibration and O–Co–O deformation modes of LaCoO${}_3$ compound. SEM micrographs clearly revealed quite spherical particles with a mean size in the range 139–178 nm and high tendency to clustering, meanwhile EDAX analysis confirmed the corresponding chemical composition with homogeneous distribution of the constituent elements. A weak paramagnetic order is observed irrespective of F/O ratio, with slight increase of the effective magnetic moment with F/O ratio; 2.72–2.93 μ${}_B$, due to the presence of more high spin states.