Tunable magnetic and magnetocaloric properties of La0.6Sr0.4MnO3 nanoparticles

Nanoparticles of La0.6Sr0.4MnO3 with different particle sizes are synthesized by the nitrate-complex auto-ignition method. The structural and magnetic properties of the samples are investigated by X-Ray diffraction (XRD), Fourier transform infra-red (FT-IR) spectroscopy, transmission electron micros...

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Bibliographic Details
Published in:Journal of applied physics 2013-12, Vol.114 (22)
Main Authors: Ehsani, M. H., Kameli, P., Ghazi, M. E., Razavi, F. S., Taheri, M.
Format: Article
Language:English
Subjects:
Applied physics
Curie temperature
Ferromagnetism
Fourier transforms
Infrared spectroscopy
Magnetic properties
Magnetism
Magnetization
Nanoparticles
Particle size
Particle spin
Perovskite structure
Perovskites
Reduction
Size effects
Spectrum analysis
Spontaneous combustion
Transmission electron microscopy
X ray spectra
X-ray diffraction
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Summary:Nanoparticles of La0.6Sr0.4MnO3 with different particle sizes are synthesized by the nitrate-complex auto-ignition method. The structural and magnetic properties of the samples are investigated by X-Ray diffraction (XRD), Fourier transform infra-red (FT-IR) spectroscopy, transmission electron microscopy (TEM), and DC magnetization measurements. The XRD study coupled with the Rietveld refinement shows that all samples crystallize in a rhombohedral structure with the space group of R-3 C. The FT-IR spectroscopy and TEM images indicate formation of the perovskite structure with the average sizes of 20, 40, and 100 nm for the samples sintered at 700, 800, and 1100 °C, respectively. The DC magnetization measurements confirm tuning of the magnetic properties due to the particle size effects, e.g., reduction in the ferromagnetic moment and increase in the surface spin disorder by decreasing the particle size. The magnetocaloric effect (MCE) study based on isothermal magnetization vs. filed measurements in all samples reveals a relatively large MCE around the Curie temperature of the samples. The peak around the Curie temperature gradually broadens with reduction of the particle size. The data obtained show that although variations in the magnetic entropy and adiabatic temperature decrease by lowering the particle size, variation in the relative cooling power values are the same for all samples. These results make this material a proper candidate in the magnetic refrigerator application above room temperature at moderate fields.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.4846758