Room temperature magnetocaloric effect, critical behavior, and magnetoresistance in Na-deficient manganite La{sub 0.8}Na{sub 0.1}MnO{sub 3}

Journal Article · Wed May 21 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4879098· OSTI ID:22304415

Dhahri, E. ^[1]; Hlil, E. K. ^[2]

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1. Laboratoire de Physique Appliquée, Faculté des Sciences de Sfax, B.P. 802, Université de Sfax, Sfax 3018 (Tunisia)
2. Institut Néel, CNRS et Université Joseph Fourier, BP 166, F-38042 Grenoble cedex 9 (France)

The La{sub 0.8}Na{sub 0.1}MnO{sub 3} oxide was prepared by the solid-state reaction and annealed in air. The X-ray diffraction data reveal that the sample is crystallized in a rhombohedral structure with R3{sup ¯}c space group. Magnetic study shows a second-order magnetic phase transition from ferromagnetic to paramagnetic state at the Curie temperature T{sub C} = 295 K. In addition, the magnetizations as a function of temperature and the magnetic field is used to evaluate the magnetic entropy change ΔS{sub M}. Then, we have deduced that the La{sub 0.8}Na{sub 0.1}MnO{sub 3} oxide has a large magnetocaloric effect at room temperature. Such effect is given by the maximum of the magnetic entropy change ΔS{sub Mmax} = 5.56, and by the Relative cooling power (RCP) factor which is equal to 235 under a magnetic field of 5 T. Moreover, the magnetic field dependence of the magnetic entropy change is used to determine the critical exponents β, γ, and δ which are found to be β = 0.495, γ = 1.083, and δ = 3.18. These values are consistent with the prediction of the mean field theory (β = 0.5, γ = 1, and δ = 3). Above all, the temperature dependence of electrical resistivity shows a metal–insulator transition at T{sub ρ}. The electrical resistivity decrease when we apply a magnetic field giving a magnetoresistance effect in the order of 60% at room temperature.

• OSTI ID: 22304415
• Journal Information: Journal of Applied Physics, Vol. 115, Issue 19; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANNEALING
CURIE POINT
ENTROPY
FORECASTING
LANTHANUM COMPOUNDS
MAGNETIC FIELDS
MAGNETIC PROPERTIES
MAGNETIZATION
MAGNETORESISTANCE
MANGANATES
MEAN-FIELD THEORY
PARAMAGNETISM
PHASE TRANSFORMATIONS
SODIUM COMPOUNDS
SOLIDS
SPACE GROUPS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0273-0400 K
TRIGONAL LATTICES
X-RAY DIFFRACTION