Magnetic and electrical behavior of La1−xAxMnO3 (A=Li, Na, K and Rb) manganites

Lakshmi, Y. Kalyana; Venkataiah, G.; Vithal, M.; Reddy, P. Venugopal

doi:10.1016/j.physb.2008.03.018

Cited by 63 publications

(11 citation statements)

References 29 publications

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“…1 shows that, after sintering at 1300°C for 24 h, the bulk samples have completely formed into a polycrystalline single phase compound where no significant extra peak is observed. Comparing to the standard ICDD (references code 01-089-0569, 00-049-0416 and 00-050-0308 for La 0.67 Ba 0.33 MnO 3 (LBMO), La 0.67 Sr 0.33 MnO 3 (LSMO) and La 0.67 Ca 0.33 MnO 3 (LCMO) respectively), LBMO and LCMO showed orthorhombic system whereas LSMO showed rhombohedral system which agree with the early report [7,10] . Different microstructures as shown in Fig.…”

Section: Discussionsupporting

confidence: 88%

“…Recently, the effect of grain boundaries in the polycrystalline manganites has been studied intensively, where the grain's shape or microstructure will be changed with different preparation process [6,7] or dopant [7][8][9] . It is found that substitution of divalent atoms with variance atomic radius and preparation process will influence the magnetic properties and electrical properties of the system [6,7] .…”

Section: Introductionmentioning

confidence: 99%

“…It is found that substitution of divalent atoms with variance atomic radius and preparation process will influence the magnetic properties and electrical properties of the system [6,7] . Therefore, in this study, an effort has been made to investigate the influence of various divalent atoms substituted in La 3+ .…”

Section: Introductionmentioning

confidence: 99%

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Effect of Divalent Ions (A = Ca, Ba and Sr) Substitution in La-A-Mn-O Manganite on Structural, Magnetic and Electrical Transport Properties

Lim¹,

Ng²,

Halim³

et al. 2009

American J. of Applied Sciences

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Problem statement: Microstructure of the grain will influence the properties of a polycrystalline manganites when different dopant is introduced. In this work, an effort had been made to investigate the influence of Ca, Ba and Sr substitution in La site. Approach: Polycrystalline manganites compound of La 0.67 A 0.33 MnO 3 where A = Ba, Sr and Ca had been prepared via conventional solid-state reaction method. The structure, microstructure, magnetic and electrical properties had been investigated using XRD, SEM, VSM and four-point probe techniques. Results: XRD spectrums showed that LBMO and LCMO were in single-phase orthorhombic structure whereas LSMO was rhombohedral structure. Scanning electron micrographs showed that LSMO had smaller average grain size as compared to LBMO. However, for LCMO, there was no clear grain boundary that can be observed and all the grains were well connected. The difference in the microstructure image might be due to the variance A-site cation that differs in grain growth. The Curie temperature, T c of LBMO and LSMO was 343.0 and 363.5 K, respectively. But the T c for LCMO was lower then 300 K. The T p for LCMO was 215 K while it was near or above 300K for LBMO and LSMO. All samples showed extrinsic Magnetoresistance (MR) effect. Higher MR was observed well below T c or T p where MR value increased monotonically with the decrease of temperature. This was associated with the different grain and grain boundary formation when different cation was substituted. LCMO displayed the highest low-field MR value (-15.82% at 0.2 T, 90 K) and high-field MR (-25.60% at 1 T, 300 K). Conclusion: Hence, electrical and magnetic transition temperature (T p and T c ) were affected by the average A-site cation radius.

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Section: Discussionsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

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Effect of Divalent Ions (A = Ca, Ba and Sr) Substitution in La-A-Mn-O Manganite on Structural, Magnetic and Electrical Transport Properties

Lim¹,

Ng²,

Halim³

et al. 2009

American J. of Applied Sciences

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“…In fact, it is a popular method for nanomaterials [3,17,18]. The main purpose of this research is the substitution of divalent atoms with different atomic radius for La in La 1−x AExMnO3, which affects the magnetic and electrical properties of it [19][20][21]. As a result, La0.7Sr0.3MnO3 (LSMO) and La0.7Ba0.3MnO3 (LBMO) were prepared, and their structural and magnetoresistance properties were analyzed.…”

Section: Introductionmentioning

confidence: 99%

Magnetoresistance temperature dependence of LSMO and LBMO perovskite manganites

2018

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La 0.7 Sr 0.3 MnO 3 (LSMO) and La 0. 7 Ba 0.3 MnO 3 (LBMO) Polycrystalline manganite nanoparticles were prepared by combustion method using glycine fuel. The ignition process was done at 360 °C and 330 °C for LSMO and LBMO, respectively. Both of the samples have rhombohedral structure using XRD analysis. The reduction is observed in electrical resistivity when external magnetic field is applied during the decrease in temperature from 300 to 89 °K, which is due to the tunneling between particles. The magnetoresistance (MR) of samples was measured in this range of temperature in both the presence and absence of a magnetic field of about 10 kG. The colossal role of a kind of extrinsic MR which is 19% and 22% for LSMO and LBMO, respectively, has been investigated in this research. The metal-insulator transition temperature of 200 °K is recorded for LBMO.

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“…The correlation between the electrical and magnetic properties in manganites gives rise to CMR effect under an external applied magnetic field [5,6] indicating that the materials have potential to be applied in magnetic devices [7]. Rare earth manganites can also be substituted by monovalent alkali metal (Li, K, Na and Rb) and this provides another pathway to discuss the structural, electrical and magnetic properties of perovskite manganites [8][9][10].…”

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confidence: 99%

Effect of Sintering Temperature on Microstructure, Electrical and Magnetic Properties of La0.85K0.15MnO3 Prepared by Sol-Gel Method

Pan

Halim

Lim

et al. 2011

J Supercond Nov Magn

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The influence of sintering temperature on the microstructure and transport properties of polycrystalline La 0.85 K 0.15 MnO 3 (LKMO) samples via sol-gel method is studied. Powder X-ray diffraction (XRD) shows that all the LKMO samples have single phase with hexagonal structure. The data obtained from XRD were analyzed by using the Rietveld refinement technique. The increase of the sintering temperature considerably promotes grain growth and improves grains connectivity. The increase of the average grain size throughout the sintering temperatures has affected the transport properties of LKMO samples. The magnetization is improved with the reduction of coercivity. The Curie temperature (T c ) was obtained from AC susceptibility data and the results were inversely proportional to the sintering temperature of the samples because the ferromagnetic properties are reduced by the increase of unit cell volume and Mn-O bond length. The electrical resistance is decreased and the metal-insulator transition temperature (T p ) is shifted towards the high temperature side, due to the improvement of grain connectivity. A phase diagram based on the measurement of T p and T c is constructed. All the LKMO samples are in the ferromagnetic-insulator phase at room temperature.

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Magnetic and electrical behavior of La1−xAxMnO3 (A=Li, Na, K and Rb) manganites

Cited by 63 publications

References 29 publications

Effect of Divalent Ions (A = Ca, Ba and Sr) Substitution in La-A-Mn-O Manganite on Structural, Magnetic and Electrical Transport Properties

Effect of Divalent Ions (A = Ca, Ba and Sr) Substitution in La-A-Mn-O Manganite on Structural, Magnetic and Electrical Transport Properties

Magnetoresistance temperature dependence of LSMO and LBMO perovskite manganites

Effect of Sintering Temperature on Microstructure, Electrical and Magnetic Properties of La0.85K0.15MnO3 Prepared by Sol-Gel Method

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