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Enhanced ferromagnetic transition temperature in nanocrystalline lanthanum calcium manganese oxide $(La_{0.67}Ca_{0.33}MnO_3)$

Shankar, Shantha K and Kar, Sohini and Subbanna, GN and Raychaudhuri, AK (2004) Enhanced ferromagnetic transition temperature in nanocrystalline lanthanum calcium manganese oxide $(La_{0.67}Ca_{0.33}MnO_3)$. In: Solid State Communications, 129 (7). pp. 479-483.

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Abstract

We report a novel, low temperature (450–600 $^oC$) route for the synthesis of highly crystalline and homogeneous nanoparticles of lanthanum calcium manganese oxide $La_{0.67}Ca_{0.33}MnO_3$ (LCMO). The nanocrystallites, with average particle size of 30 nm, possess a ferromagnetic–paramagnetic transition temperature $(T_c)$ of 300 K, which is about 50 K higher than that of a bulk single crystal. The transition temperature was found to be inversely proportional to the particle size. The Rietveld analysis of the powder X-ray diffraction data of the phase-pure nanopowders reveals that the particle size reduction leads to a significant contraction of the unit cell volume and a reduction of the unit cell anisotropy. We propose that these two lattice effects are responsible for the observed enhancement in $T_c$.

Item Type: Journal Article
Additional Information: The copyright belongs to Elsevier.
Keywords: A.Nanostructures;B.Chemical synthesis;C.Crystal structure and symmetry;D.Phase transitions
Department/Centre: Division of Chemical Sciences > Materials Research Centre
Division of Physical & Mathematical Sciences > Physics
Date Deposited: 01 Jun 2006
Last Modified: 19 Sep 2010 04:28
URI: http://eprints.iisc.ernet.in/id/eprint/7264

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