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Low temperature synthesis, structural characterization, and zero-field resistivity of nanocrystalline $La_{1-x}MnO_{3+\delta}$ (0.0\leq{x}\leq0.3) manganites

Nagabhushana, BM and Chakradhar, Sreekanth RP and Ramesh, KP and Shivakumara, C and Chandrappa, GT (2006) Low temperature synthesis, structural characterization, and zero-field resistivity of nanocrystalline $La_{1-x}MnO_{3+\delta}$ (0.0\leq{x}\leq0.3) manganites. In: Materials Research Bulletin, 41 (9). pp. 1735-1746.

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Abstract

This paper reports the synthesis of nanocrystalline strontium doped manganites by a simple and instantaneous solution combustion method, which is a low temperature initiated route to prepare fine-grained oxide powders with good surface area. Rietveld refinement of X-ray data indicates that the as-formed manganites exhibit a cubic phase with space group Pm3m. However calcined (900 °C, 6 h) samples transform into rhombohedral phase with space group R-3c. The scanning electron micrographs of the powders reveal that the sizes of very fine primary particles which are in an agglomerated form, decrease as strontium content increases. The infrared spectra of lanthanum manganites show two active modes at $400\hspace{2mm}and\hspace{2mm}600\hspace{1mm}cm^{-1}$. From zero-field resistivity measurements, it is found that all the samples exhibit metal–insulator transition $(T_{M-I})$ in the range of 219–252 K, which is low as compared to the samples prepared by ceramic route. The lower $(T_{M-I})$ values might be due to smaller particle sizes in the range of 25–45 nm.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Elsevier.
Keywords: Magnetic materials;A. Oxides;B. Chemical synthesis;C. X-ray diffraction;D. Electrical properties
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 10 Oct 2006
Last Modified: 19 Sep 2010 04:32
URI: http://eprints.iisc.ernet.in/id/eprint/8822

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