Effect of particle size on the magnetic and transport properties of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">La</mml:mi></mml:mrow><mml:mrow><mml:mn>0.875</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Sr</mml:mi></mml:mrow><mml:mrow><mml:mn>0.125</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">MnO</mml:mi></mml:m

Dutta, A; Gayathri, N.; Ranganathan, R.

doi:10.1103/physrevb.68.054432

Cited by 161 publications

(105 citation statements)

References 40 publications

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“…The ∆T values are found to decrease from a large value of 108 to 24 K as the sintering temperature increases continuously and in fact, a similar difference between T C and T P has been reported earlier [14]. The observed difference between the two transition temperatures may be explained as outlined here.…”

Section: Magnetic and Electricalsupporting

confidence: 87%

“…It is clear from the table that T C values decrease with increasing sintering temperature thereby indicating that T C is decreasing with increasing particle size. The observed behavior may be explained following the work by Dutta et al [14]; According to these authors, the magnetic and transport properties of the perovskite manganites are strongly coupled and are very sensitive to Mn-O-Mn bond angle and Mn-O bond length. It has been found that a decrease in magnetization and an increase in resistivity occur as we decrease the particle size, due to broken Mn-O-Mn bonds at the surface of smaller particles that hamper exchange interaction and degrade connectivity for electron conduction, but in this case it seems that the spin interaction increases and the connectivity improves as we decrease the particle size.…”

Section: Magnetic and Electricalmentioning

confidence: 78%

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Influence of sintering temperature on resistivity, magnetoresistance and thermopower of La0.67Ca0.33MnO3

2008

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A systematic investigation of La 0.67 Ca 0.33 MnO 3 manganites has been undertaken, mainly to understand the influence of varying crystallite size (nano meter range) on electrical resistivity, magnetic susceptibility and thermoelectric power. The materials were prepared by the sol-gel method of sintering at four different temperatures between 800-1100°C. The samples were characterized by X-ray diffraction and data were analyzed using Rietveld refinement. The metal-insulator transition temperatures (T P ) are found to increase with increasing sintering temperatures, while the magnetic transition temperatures (T C ) decrease.The electrical resistivity and thermoelectric power data at low temperatures (T < T P ) have been analyzed by considering various scattering phenomena, while the high temperature (T > T P ) data were analyzed with Mott's small polaron hopping conduction mechanisms.

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Section: Magnetic and Electricalsupporting

confidence: 87%

Section: Magnetic and Electricalmentioning

confidence: 78%

Influence of sintering temperature on resistivity, magnetoresistance and thermopower of La0.67Ca0.33MnO3

2008

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“…In addition the values of T N of NiO close to the former study [29]. It can also be seen that a relatively large difference between T ms and T C observed for each sample in Table 1, agrees with the difference reported previously [30][31][32]. The difference is due to the grain boundary that can influence onto T ms shifting it to a lower temperatures [29,30] but does not affect T C , which is an intrinsic property of the magnetic core of grains.…”

Section: Magnetizationsupporting

confidence: 81%

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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“…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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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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Effect of particle size on the magnetic and transport properties ofLa0.875Sr0.125MnO

Cited by 161 publications

References 40 publications

Influence of sintering temperature on resistivity, magnetoresistance and thermopower of La0.67Ca0.33MnO3

Influence of sintering temperature on resistivity, magnetoresistance and thermopower of La0.67Ca0.33MnO3

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

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

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