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Magnetism and magnetocaloric effect in nanocrystalline La0.67Ca0.33Mn0.9V0.1O3synthesized by nebulized spray pyrolysis

Nisha, P. and Pillai, S. Savitha and Darbandi, Azad and Misra, Ajay and Suresh, K. G. and Varma, Manoj Raama and Hahn, Horst (2010):
Magnetism and magnetocaloric effect in nanocrystalline La0.67Ca0.33Mn0.9V0.1O3synthesized by nebulized spray pyrolysis.
In: Journal of Physics D: Applied Physics, 43 (13), IOP Publishing, pp. 135001-1, ISSN 0022-3727,
[Online-Edition: http://dx.doi.org/10.1088/0022-3727/43/13/135001],
[Article]

Abstract

Vanadium (V) substituted La0.67Ca0.33MnO3 was synthesized in the nanocrystalline form using nebulized spray pyrolysis. Highly uniform nanoparticles of average size in the range 30–40 nm as revealed by transmission electron microscopic studies were prepared. Rietveld refinement of XRD patterns shows that the sample adopts an orthorhombic structure with the Pnma space group. The systematic change in lattice parameters and magnetic phase transition (TC = 252 K) as compared with those of nanocrystalline La0.67Ca0.33MnO3 (TC = 260 K) indicate the substitutional effect of V. M–H curves in a certain temperature range reflect the superparamagnetic nature of the sample. The average particle size (∼28 nm) of the superparamagnetic clusters obtained from the Langevin fit is coincident with that of the nanocrystalline clusters revealed by the high-resolution transmission electron microscopy images. The Arrott plots reveal the first order character of magnetic phase transition of the sample. The peak magnetic entropy change (�Smax) of these nanopowders is estimated to be about 4.5 J kg−1 K−1 for a magnetic field of 5 T at 252 K. Compared with the bulk La0.67Ca0.33Mn0.9V0.1O3, the entropy change of the nanoparticles is found to be smaller, but the entropy change occurs over a broad temperature range, giving rise to a large relative cooling power.

Item Type: Article
Erschienen: 2010
Creators: Nisha, P. and Pillai, S. Savitha and Darbandi, Azad and Misra, Ajay and Suresh, K. G. and Varma, Manoj Raama and Hahn, Horst
Title: Magnetism and magnetocaloric effect in nanocrystalline La0.67Ca0.33Mn0.9V0.1O3synthesized by nebulized spray pyrolysis
Language: English
Abstract:

Vanadium (V) substituted La0.67Ca0.33MnO3 was synthesized in the nanocrystalline form using nebulized spray pyrolysis. Highly uniform nanoparticles of average size in the range 30–40 nm as revealed by transmission electron microscopic studies were prepared. Rietveld refinement of XRD patterns shows that the sample adopts an orthorhombic structure with the Pnma space group. The systematic change in lattice parameters and magnetic phase transition (TC = 252 K) as compared with those of nanocrystalline La0.67Ca0.33MnO3 (TC = 260 K) indicate the substitutional effect of V. M–H curves in a certain temperature range reflect the superparamagnetic nature of the sample. The average particle size (∼28 nm) of the superparamagnetic clusters obtained from the Langevin fit is coincident with that of the nanocrystalline clusters revealed by the high-resolution transmission electron microscopy images. The Arrott plots reveal the first order character of magnetic phase transition of the sample. The peak magnetic entropy change (�Smax) of these nanopowders is estimated to be about 4.5 J kg−1 K−1 for a magnetic field of 5 T at 252 K. Compared with the bulk La0.67Ca0.33Mn0.9V0.1O3, the entropy change of the nanoparticles is found to be smaller, but the entropy change occurs over a broad temperature range, giving rise to a large relative cooling power.

Journal or Publication Title: Journal of Physics D: Applied Physics
Volume: 43
Number: 13
Publisher: IOP Publishing
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Joint Research Laboratory Nanomaterials
Date Deposited: 15 Feb 2013 10:19
Official URL: http://dx.doi.org/10.1088/0022-3727/43/13/135001
Identification Number: doi:10.1088/0022-3727/43/13/135001
Funders: Dr Manoj Raama Varma would like to thank the German Academic Exchange Service DAAD for support during his visit to INT, Karlsruhe., Nisha and Dr Manoj Raama Varma would like to thank the Department of Science and Technology, Government of India, for providing the HRTEM facility at NIIST, Trivandrum, and Defence Research and Development Organization, Government of India,, for supporting the project.
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