Dependence of structural/morphological and magnetic properties of LaCoO 3 nanoparticles prepared by citrate nitrate auto
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Dependence of structural/morphological and magnetic properties of LaCoO3 nanoparticles prepared by citrate nitrate auto combustion V. Anslin Ferby1,2 · A. Moses Ezhil Raj1,2 · M. Bououdina3 Received: 20 July 2020 / Accepted: 17 October 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Perovskite LaCoO3 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 LaCoO3 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 LaCoO3 phase, whereas the strong absorption band at 589 cm−1 was assigned to Co–O stretching vibration and O–Co–O deformation modes of L aCoO3 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 μB, due to the presence of more high spin states. Keywords Combustion synthesis · Rietveld analysis · FTIR spectroscopy · Effective magnetic moment
1 Introduction Perovskites are designated as mixed oxides with chemical formula ABO3, containing A-cation as rare earth and B-cation as metal, where partial substitutions on both A and B sites leads to a wide variety of compounds. Although most of the phases are similar to a perfect cubic crystal structure, particular attention has been devoted to better understanding the crystallographic behavior of perovskites upon compositional modifications. It has been reported that most of the obtained phases present structural distortion, as consequence the symmetry is lowered forming new structures such as orthorhombic, tetragonal, rhombohedral, trigonal and so on. The above changes are found to be dependent on various experimental parameters including temperature, pressure, * V. Anslin Ferby [email protected] 1
Department of Physics and Research Centre, Scott Christian College (Autonomous), Nagercoil 629 003, India
2
Manonmaniam Sundaranar University, Abishekapatti, Tirunelveli 627012, India
3
Department of Physics, College of Science, The University of Bahrain, P.O Box 32038, Zallaq, Kingdom of Bahrain
chemical composition, and electric field. For example, with the rise of annealing temperature, it was found that perovskite compounds were subjected to phase transition were obtained following the gradual change into higher symmetry to end up with a cubic phase. Due to such crystal structure modifications, the electronic, ele
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