Effect of Al substitution on magnetocaloric effect in La0.57Nd0.1Sr0.33Mn1−xAlxO3 (0.0≤x≤0.30) polycrystalline near room temperature

Tka, E.; Cherif, K.; Dhahri, J.; Dhahri, E.; Belmabrouk, Hafedh; Hlil, E.K.

doi:10.1016/j.jallcom.2011.12.100

Cited by 28 publications

(5 citation statements)

References 39 publications

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“…This shows that the substitution at the La site does ultimately affect the Mn site ion in the La 1−x M x MnO 3 perovskite structure. Transfer of itinerant e g electrons between neighboring Mn 3+ and Mn 4+ ions through O 2− ions, in accordance with the Zener double exchange model [3], results in ferromagnetic interaction due to the on-site Hund's coupling. Recently, it has been reported that the origin of the CMR effect is due to the existence of quenched disorder which induces nanoscale spin clusters in the paramagnetic region [4].…”

Section: Introductionsupporting

confidence: 72%

Influence of Na Addition on Magnetic and Magnetocaloric Effects of La0.67Pb0.13Na0.2MnO3 Ceramics

Zaidi

Dhahri

et al. 2016

J Supercond Nov Magn

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Structural, magnetic, magnetocaloric, and electrical properties are reported for mixed-valence manganite La 0.67 Pb 0.13 Na 0.2 MnO 3 . X-ray diffraction reveals that the sample crystallizes in the rhombohedric structure with the R-3c space group. The magnetic properties of the polycrystalline La 0.67 Pb 0.13 Na 0.2 MnO 3 compound are discussed in detail, based on the susceptibility, magnetization, and isotherm. The sample presents a ferromagnetic property with T C = 275 K and a Griffiths phase at T G = 325 K which gives the existence of ferromagnetic clusters in the paramagnetic domain. A large deviation is usually observed between field cooled (FC) and zero field cooled (ZFC). M(T ) is a low temperature below the blocking temperature. At 40 K, a spin-glass or a cluster-glass state is seen to arise from a ferromagnetic state. This is caused by the competition between the antiferromagnetic and ferromagnetic interactions. The electrical properties show the presence of a metal-semiconductor transition at T M−Sc . To understand the dependence of disorder with the transport mechanism, we used the phenomenological equation for Ahmed Dhahri jemai 2000@outlook.fr 1 Laboratoire de la matière condensée et des nanosciences, resistivity under a percolation approach, which is dependent on the phase segregation of a paramagnetic semiconductor and ferromagnetic metallic regions.

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Section: Introductionsupporting

confidence: 72%

Influence of Na Addition on Magnetic and Magnetocaloric Effects of La0.67Pb0.13Na0.2MnO3 Ceramics

Zaidi

Dhahri

et al. 2016

J Supercond Nov Magn

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“…We can then obtain the values of versus the frequency and at several temperatures. The relative dynamic permeability of the toroidal core made from the nanocrystalline FeNbCuSiB reads [9]:…”

Section: Complex Permeabilitymentioning

confidence: 99%

“…To improve the efficiency of the magnetic components such as power converters and to avoid the need of sophisticated cooling systems, it is necessary to limit the heat generation in the magnetic components. In the design of a power converter, it is important to choose the appropriate alloy from a magnetic point of view but it is also important to take into account the thermal constraints due to heat generation and the dependence of the magnetic properties on the temperature [4][5][6][7][8][9]. In this paper, the complex permeability of a toroidal core of nanocrystalline FeNbCuSiB alloys is indirectly measured versus the frequency and at different temperatures ranging from 20°C to 180°C.…”

Section: Introductionmentioning

confidence: 99%

Complex Permeability Measurements in a Nanocrystalline Toroidal Core

2016

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In the design of power electronic converters, the choice of the suitable magnetic alloys and the measurement of the variations of their magnetic properties versus the temperature are fundamental issues. A theoretical model based on Neel theory and that takes into account wall displacement and coherent rotation was elaborated to derive the expression of the complex permeability versus the frequency. The static and the dynamic behavior are considered. The dependence of temperature is implicit in this model, i.e. the parameters involved in the expression of the complex permeability may depend on the temperature. An impedance analyzer has been used to measure the open circuit and short circuit complex impedances of a toroidal core versus the frequency at several temperatures ranging from 20°C to 180°C. The complex permeability of the material is then deduced. Finally, the theoretical model is used to identify the domain susceptibility and the anisotropy energy of the materials. The effect of temperature on these parameters is analyzed. The result obtained are valuable for the design of a power electronic converters from the magnetic and thermal viewpoints. The results prove the need for the combination of heat transfer and magnetic mechanisms at the design.

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“…Among them, La(Ca,Sr)MnO 3 manganites are considered the most suitable materials to be used in magnetic refrigeration, owing to their physical properties, such as small magnetic and thermal hysteresis, a large magnetocaloric effect around the paramagnetic to ferromagnetic transition temperature (Curie temperature, T C ), and broad working temperature ranges due to easy controlling of the Curie temperature by doping [9,10,11]. In addition, manganites have low preparation costs, chemical stability (no oxidation), and high electrical resistance [12,13].…”

Section: Introductionmentioning

confidence: 99%

Preparation of La0.7Ca0.3−xSrxMnO3 Manganites by Four Synthesis Methods and Their Influence on the Magnetic Properties and Relative Cooling Power

et al. 2019

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Manganites of the family La0.7Ca0.3−xSrxMnO3 were fabricated by four preparation methods: (a) the microwave-assisted sol-gel Pechini method; (b) sol-gel Pechini chemical synthesis; (c) solid-state reaction with a planetary mill; and (d) solid-state reaction with an attritor mill, in order to study the effect of the preparation route used on its magnetocaloric and magnetic properties. In addition, the manganites manufactured by the Pechini sol-gel method were compacted using Spark Plasma Sintering (SPS) to determine how the consolidation process influences its magnetocaloric properties. The Curie temperatures of manganites prepared by the different methods were determined in ~295 K, with the exception of those prepared by a solid-state reaction with an attritor mill which was 301 K, so there is no correlation between the particle size and the Curie temperature. All samples gave a positive slope in the Arrot plots, which implies that the samples underwent a second order Ferromagnetic (FM)–Paramagnetic (PM) phase transition. Pechini sol-gel manganite presents higher values of Relative Cooling Power (RCP) than the solid-state reaction manganite, because its entropy change curves are smaller, but wider, associated to the particle size obtained by the preparation method. The SPS technique proved to be easier and faster in producing consolidated solids for applications in active magnetic regenerative refrigeration compared with other compaction methods.

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Effect of Al substitution on magnetocaloric effect in La0.57Nd0.1Sr0.33Mn1−xAlxO3 (0.0≤x≤0.30) polycrystalline near room temperature

Cited by 28 publications

References 39 publications

Influence of Na Addition on Magnetic and Magnetocaloric Effects of La0.67Pb0.13Na0.2MnO3 Ceramics

Influence of Na Addition on Magnetic and Magnetocaloric Effects of La0.67Pb0.13Na0.2MnO3 Ceramics

Complex Permeability Measurements in a Nanocrystalline Toroidal Core

Preparation of La0.7Ca0.3−xSrxMnO3 Manganites by Four Synthesis Methods and Their Influence on the Magnetic Properties and Relative Cooling Power

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