The effect of the annealing temperature on the structural and magnetic properties of the manganites compounds

Othmani, S.; Bejar, M.; Dhahri, E.; Hlil, E. K.

doi:10.1016/j.jallcom.2008.08.005

Cited by 47 publications

(14 citation statements)

References 14 publications

(14 reference statements)

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“…In comparison with our previous results [8], it is illustrated that with the increase in the annealing temperature, the particle size of samples increased, confirming that the annealing temperature promotes the grain growth of the samples [15][16][17]24,25].…”

Section: Resultssupporting

confidence: 75%

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Impact of Annealing Temperature on the Physical Properties of the Lanthanum Deficiency Manganites

2017

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Abstract:The lanthanum deficiency manganites La 0.8−x x Ca 0.2 MnO 3 (x = 0, 0.1 and 0.2), where is a lanthanum vacancy, were prepared using the classic ceramic methods with different thermal treatments (1373 K and 973 K). The structural, magnetic, and magnetocaloric properties of these compounds were studied as a function of annealing temperature. It was noted that the annealing temperature did not affect the crystal structure of our samples (orthorhombic structure with Pnma space group). Nevertheless, a change in the variation of the unit cell volume V, the average bond length d Mn-O , and the average bond angles θ Mn-O-Mn were observed. Magnetization versus temperature study has shown that all samples exhibited a magnetic transition from ferromagnetic (FM) to paramagnetic (PM) phase with increasing temperature. However, it can be clearly seen that the annealing at 973 K induced an increase of the magnetization. In addition, the magnetocaloric effect (MCE) as well as the relative cooling power (RCP) were estimated. As an important result, the values of MCE and RCP in our Lanthanum-deficiency manganites are reported to be near to those found in gadolinium, considered as magnetocaloric reference material.

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Section: Resultssupporting

confidence: 75%

“…Other research works have shown that the physical properties of ceramics are also sensitive to the value of the sintering temperature [15][16][17][18]. Actually, all these research works have confirmed that the electronic, magnetic, and transport properties are significantly affected by the grain size.…”

Section: Introductionmentioning

confidence: 87%

Impact of Annealing Temperature on the Physical Properties of the Lanthanum Deficiency Manganites

2017

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“…The pure saturation and the sharp drop of magnetization in the parent LBMO support the high homogeneity of the samples in the XRD patterns, while the drop of LBMO/NiO is due to the existence of non-homogeneity NiO phase [26]. In the parent LBMO the annealing process increases magnetization and decreases T C in agreement with La 1-x Ce x MnO 3 [27]. As for the annealed LBMO sample at 900 °C, its higher T C , may be due to an increase in Mn-O bond length which leads to the charge delocalization and promotes hopping of the electrons through the Mn-O-Mn path.…”

Section: Magnetizationsupporting

confidence: 57%

The annealing influence onto the electrical and magnetic behavior of magnetoresistive/insulator system

Ahmed

Mohamed

et al. 2016

Low Temperature Physics

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This investigation is mainly concerned with the effect of annealing temperature (600, 700, 800 and 900 °C) in air for (La 0.7 Ba 0.3 MnO 3 ) 1-x /(NiO) x with x = 0 and x = 0.10 samples. It was shown that the annealing temperature does not affect the structure and parameters of rhombohedral lattice of the samples. However, it is observed that the annealing treatment has a notable effect on the electrical resistivity and the metal-semiconductor transition temperature T ms . Temperature dependent magnetization measurements showed a decrease in Curie temperature T C with annealing temperature. In the same time, annealing process decreases the magnetoresistance of La 0.7 Ba 0.3 MnO 3 , in contrast to (La 0.7 The magnetoresistive material was mixed with an insulator material to enhance the extrinsic CMR that depending on grain boundaries [6] and spin tunneling [7], that CMR may increase under low magnetic fields known as low field magnetoresistance (LFMR). The importance of LFMR refers to use low magnetic field to get high values of MR what is making it useful for applications. This LFMR can be affected by other several factors; one of them is annealing temperature that can affect the grain size and hence the physical properties including LFMR. An annealing effect has a little attention in this direction, especially in LBMO/insulator. Therefore in this work the effects of annealing temperature on the electrical, magnetic, magnetoresistance and thermoelectric properties of La 0.7 Ba 0.3 MnO 3 (LBMO) and (La 0.7 Ba 0.3 MnO 3 ) 0.9 /(NiO) 0.1 (LBMO/NiO) are examined. Experimental(La 0.7 Ba 0.3 MnO 3 ) 1-x /(NiO) x ceramic samples were prepared by the conventional solid state reaction method (x = = 0.0 & 0.10). La 2 O 3 , BaCO 3 and MnCO 3 raw materials were mixed in stoichiometric proportions, ground, pelletized and calcined at 900 °C for 24 h. It was reground again and pelletized and then sintered at 1100 °C for 24 h. NiO insulator was added in stoichiometric portions to the sintered La 0.7 Ba 0.3 MnO 3 compound and lightly ground, then pressed and put in 1000 °C for 24 h. The composites of LBMO and LBMO/NiO annealed for 2 h at 600, 700, 800 and 900 °C. Electrical resistivity was measured by van der Pauw technique in the presence and absence of 0.6 T magnetic field. Samples were examined by x ray, using Brucker (Axs-D& Advance) powder diffractometer at room temperature with Cu (K α ) radiation (λ = 1.5406 Å). The microstructure was investigated by Jeol JSM-6610LV

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“…Studies demonstrate that the mixed-valence perovskite manganites exhibit both large magnetocaloric effect (MCE) and colossal magnetoresistance (CMR) around the ferromagnetic ordering temperature (T C ) [3][4][5], which makes them promising materials for magnetic refrigeration. So far, the MCE in perovskite-type manganese oxide has been widely studied and referenced in a large number of publications.…”

Section: Introductionmentioning

confidence: 99%

Crystal structure, magnetic and magnetocaloric properties of aluminum-doped La0.6Sr0.4MnO3 perovskites

et al. 2017

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In this paper, we report on the structural, magnetic and magnetocaloric properties of a series of nanocrystallines La 0.6 Sr 0.4 Mn 1-x Al x O 3 (0 B x B 0.2) which were prepared by the sol-gel method. The X-ray powder diffraction showed that all our synthesized samples were of a single phase and have crystallized in the hexagonal symmetry with R 3c space group. Magnetic measurements showed that the sample exhibits a ferromagnetic-to-paramagnetic phase transition at a Curie temperature close to 206 K. The maximum value of the magnetic entropy change DS max M was found to be 1.09 J kg -1 K -1 for an applied magnetic field of 5T. At this value of magnetic field, the relative cooling power was 141 J kg -1 . Our result on magnetocaloric properties suggests that La 0.6 Sr 0.4 Mn 1-x Al x O 3 nanopowder with (0 B x B 0.2) is attractive as a potential refrigerant for high-temperature magnetic refrigeration.

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The effect of the annealing temperature on the structural and magnetic properties of the manganites compounds

Cited by 47 publications

References 14 publications

Impact of Annealing Temperature on the Physical Properties of the Lanthanum Deficiency Manganites

Impact of Annealing Temperature on the Physical Properties of the Lanthanum Deficiency Manganites

The annealing influence onto the electrical and magnetic behavior of magnetoresistive/insulator system

Crystal structure, magnetic and magnetocaloric properties of aluminum-doped La0.6Sr0.4MnO3 perovskites

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