Magnetic entropy change and relative cooling power of Gd3Ni6Al2 and Tb3Ni6Al2 compounds

2013 ◽  
Vol 156 ◽  
pp. 54-58 ◽  
Author(s):  
D.X. Li ◽  
S. Nimori ◽  
D. Aoki
Keyword(s):  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Relative Cooling Power ◽  
Cooling Power ◽  
Magnetic Entropy

Field Dependence of the Refrigerant Capacity for La0.6Ca0.4MnO3 Manganite

2009 ◽  
Vol 154 ◽  
pp. 163-168 ◽  
Author(s):  
R.A. Szymczak ◽  
Aleksandra Kolano-Burian ◽  
Roman Kolano ◽  
R. Puzniak ◽  
V.P. Dyakonov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Curie Temperature ◽  
Statistical Model ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Relative Cooling Power ◽  
Cooling Power ◽  
Magnetic Entropy ◽  
Refrigerant Capacity ◽  
Jahn Teller

The magnetocaloric effect in La0.6Ca0.4MnO3 manganite has been investigated. The isothermal magnetization versus applied magnetic field at various temperatures in the vicinity of Curie temperature was measured, and the temperature dependence of magnetic entropy change was determined using Maxwell’s relation. This value is comparable to that in Gd. Nevertheless, the relative cooling power of La0.6Ca0.4MnO3 was shown to be considerably lower than that of Gd. The experimental results have been analyzed in frames of a phenomenological statistical model. This model considers explicitly Jahn-Teller interactions and allows prediction of the field dependences of the magnetic entropy change and the relative cooling power.

scholarly journals Observation of a Broadened Magnetocaloric Effect in Partially Crystallized Gd60Co40 Amorphous Alloy

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1741
Author(s):  
Ping Han ◽  
Ziyang Zhang ◽  
Jia Tan ◽  
Xue Zhang ◽  
Yafang Xu ◽  
...  
Keyword(s):  
Amorphous Alloy ◽  
Magnetocaloric Effect ◽  
Magnetic Entropy Change ◽  
Amorphous Matrix ◽  
Thermodynamic Cycle ◽  
Entropy Change ◽  
Cooling Power ◽  
Magnetic Entropy ◽  
Amorphous Precursor ◽  
Space Group

To investigate the effect of crystallization treatment on the structure and magnetocaloric effect of Gd60Co40 amorphous alloy, the melt-spun ribbons were annealed at 513 K isothermally for 20, 40 and 60 min. The results indicate that, with increasing annealing time, the Gd4Co3 (space group P63/m) and Gd12Co7 (space group P21/c) phases precipitated from the amorphous precursor in sequence. In particular, in the samples annealed for 40 and 60 min, three successive magnetic transitions corresponding to the phases of Gd4Co3, Gd12Co7 and remaining amorphous matrix were detected, which induced an overlapped broadened profile of magnetic entropy change (|ΔSM|) versus temperature. Under magnetic field changing from 0 to 5 T, |ΔSM| values of 6.65 ± 0.1 kg−1·K−1 and 6.44 ± 0.1 J kg−1·K−1 in the temperature spans of 180–196 K and 177–196 K were obtained in ribbons annealed for 40 and 60 min, respectively. Compared with the fully amorphous alloy, the enhanced relative cooling power and flattened magnetocaloric effect of partially crystallized composites making them more suitable for the Ericsson thermodynamic cycle.

scholarly journals Tuning Magnetic Entropy Change and Relative Cooling Power in La0.7Ca0.23Sr0.07MnO3 Electrospun Nanofibers

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 435
Author(s):  
Luis Andrés Burrola Gándara ◽  
Lizeth Vázquez Zubiate ◽  
Diana M. Carrillo Flores ◽  
José T. Elizalde Galindo ◽  
Carlos Ornelas ◽  
...  
Keyword(s):  
Magnetic Entropy Change ◽  
Mixed Valence ◽  
Electrospun Nanofibers ◽  
Entropy Change ◽  
Heat Treatments ◽  
Cooling Power ◽  
Magnetic Entropy ◽  
Transmission Electron ◽  
Heat Treated ◽  
T Values

We present experimental evidence about the magnetocaloric tuning effect in one-dimensional nanostructure fibers mixed-valence manganite as synthesized by electrospinning techniques and under heat treatments of 973, 1073 and 1173 K. The stoichiometry obtained is La0.7Ca0.23Sr0.07MnO3 and Rietveld refinement indicates a single-phase with an orthorhombic (Pnma) crystal structure. Scanning and transmission electron microscopy observations indicate coalescence in granular colonies of La0.7Ca0.23Sr0.07MnO3 nanoparticles to conform nanofibers. Magnetic entropy change is tuned due to heat treatments at 1173 K with maximum values of 1, 1.82 and 2.51 J/kgK for applied external magnetic fields of μ0H = 1, 2 and 3T, respectively, with a maximum magnetic entropy difference at a Curie temperature of 293 K (furthermore, second-order magnetic phase transition was observed). Additionally, for a magnetic field, ~μ0H = 3 T values of 49, 95 and 143 J/kg for 973, 1073 and 1173 K heat-treated samples were obtained.

scholarly journals Magnetocaloric effect in Sr2FeMoO6/Ag composites

2015 ◽  
Vol 9 (1) ◽  
pp. 11-15 ◽  
Author(s):  
Mahmoud Hamad
Keyword(s):  
Magnetocaloric Effect ◽  
Magnetic Entropy Change ◽  
Double Perovskite ◽  
Entropy Change ◽  
Heat Capacity Change ◽  
Cooling Power ◽  
Magnetic Entropy ◽  
Low Field ◽  
Capacity Change ◽  
Magnetocaloric Properties

The enhanced low-field magnetocaloric effect was investigated for double perovskite Sr2FeMoO6 - silver (SFMO/Ag) composites with 0, 5 and 10 wt.% of Ag. A phenomenological model was used to predict magnetocaloric properties of SFMO/Ag composites, such as magnetic entropy change, heat capacity change and relative cooling power. It was shown that magnetic entropy change (?S M) peaks of SFMO/Ag span over a wide temperature region, which can significantly improve the global efficiency of the magnetic refrigeration. Furthermore, the ?S M distribution of the SFMO/Ag composites is much more uniform than that of gadolinium. Through these results, SFMO/Ag composite has some potential application for magnetic refrigerants in an extended high-temperature range.

Magnetic and magnetocaloric effect in a stuffed honeycomb polycrystalline antiferromagnet GdInO3

2021 ◽  
Author(s):  
Yao-Dong Wu ◽  
Wei-Wei Duan ◽  
Qiu-Yue Li ◽  
Yong-Liang Qin ◽  
Zhen-Fa Zi ◽  
...  
Keyword(s):  
Magnetocaloric Effect ◽  
Magnetic Entropy Change ◽  
Magnetic System ◽  
Magnetic Hysteresis ◽  
Entropy Change ◽  
Cooling Power ◽  
Magnetic Entropy ◽  
Antiferromagnetic Ordering ◽  
Magnetocaloric Properties ◽  
The Magnetic Field

Abstract The magnetic and magnetocaloric properties were studied in a stuffed honeycomb polycrystalline antiferromagnet GdInO3. The onset temperature of antiferromagnetic ordering was observed at ~ 2.1 K. Negligible thermal and magnetic hysteresis suggest a reversible magnetocaloric effect (MCE) in the GdInO3 compound. In the magnetic field changes of 0–50 kOe and 0–70 kOe, the maximum magnetic entropy change values are 9.65 J/kg K and 18.37 J/kg K, respectively, near the liquid helium temperature, with the corresponding relative cooling power values of 115.01 J/kg and 211.31 J/kg. The MCE investigation of the polycrystalline GdInO3 serves to illuminate more exotic properties in this frustrated stuffed honeycomb magnetic system.

Iron Oxide-based Magnetic Nanoparticles for High Temperature Span Magnetocaloric Applications

2014 ◽  
Vol 1708 ◽  
Author(s):  
V. Chaudhary ◽  
R. V. Ramanujan
Keyword(s):  
High Temperature ◽  
Transition Temperature ◽  
Magnetic Nanoparticles ◽  
Room Temperature ◽  
Magnetic Entropy Change ◽  
Average Crystallite Size ◽  
Entropy Change ◽  
Superparamagnetic Nanoparticles ◽  
Cooling Power ◽  
Magnetic Entropy

ABSTRACTThe magnetocaloric effect of chemically synthesized Mn0.3Zn0.7Fe2O4 superparamagnetic nanoparticles with average crystallite size of 11 nm is reported. The magnitude of the magnetic entropy change (ΔSM), calculated from magnetization isotherms in the temperature range of 30 K to 400 K, increases from - 0.16 J-kg-1K-1 for a field of 1 T to - 0.88 J-kg-1K-1 for 5 T at room temperature. Our results indicate that ΔSM values are much higher than primarily reported values for this class of nanoparticles. ΔSM is not limited to the ferromagnetic-paramagnetic transition temperature; instead, it occurs over a broad range of temperatures, resulting in high relative cooling power.

scholarly journals Influence of Sr Doping on Magnetic and Magnetocaloric Properties of Nd0.6Sr0.4MnO3

2020 ◽  
Vol 36 (1) ◽  
Author(s):  
Thi Anh Ho ◽  
Huyen Ngoc Nguyen ◽  
Thang Duc Pham
Keyword(s):  
Magnetic Field ◽  
Magnetic Entropy Change ◽  
Magnetic Order ◽  
Entropy Change ◽  
Solid State Reaction Method ◽  
Cooling Power ◽  
Magnetic Entropy ◽  
Magnetocaloric Properties ◽  
Reduced Temperature ◽  
Curie Temperature Tc

Nd0.6Sr0.4MnO3 sample is fabricated by a solid-state reaction method and its magnetic, magnetocaloric properties are investigated. The Curie temperature, TC, at which a ferromagnetic-paramagnetic transition occurs is about 270 K. Based on an analysis using the Banejee’s criterion for the experiment results of magnetic-field dependences of magnetization and the universal curves of the normalized entropy change versus reduced temperature, we assess magnetic order existing in this sample. Furthermore, the maximum magnetic entropy change, which occurs near TC, measured at a magnetic field span of 50 kOe is about 6.0 J/kg.K corresponds to relative cooling power of 250 J/kg. These values are comparable to those of other manganites.

scholarly journals Magnetocaloric properties of La0.666Sr0.373Mn0.943Cu0.018O3

2017 ◽  
Vol 11 (3) ◽  
pp. 225-228 ◽  
Author(s):  
Mahmoud Hamad
Keyword(s):  
Magnetocaloric Effect ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Cooling Power ◽  
Magnetic Entropy ◽  
Active Magnetic Regenerator ◽  
Magnetocaloric Properties ◽  
Magnetic Specific Heat ◽  
Prospective Application ◽  
Magnetic Regenerator

Magnetocaloric properties of La0.666Sr0.373Mn0.943Cu0.018O3 (LSMCO) perovskite (such as magnetic entropy change, full-width at half-maximum, relative cooling power and magnetic specific heat change) at applied magnetic field of 0.05 T were calculated using the phenomenological model. The results indicate the prospective application of LSMCO due to high magnetocaloric effect near the Curie temperature. Furthermore, the magnetocaloric properties of LSMCO sample are comparable with magnetocaloric properties of MnAs film, La1-xCdxMnO3 and La1.25Sr0.75MnCoO6, and significantly larger than that of Gd1-xCaxBaCo2O5.5 and Ge0.95Mn0.05. It is recommended that magnetocaloric effect of LSMCO can be used as a promising practical material of an apparatus based on the active magnetic regenerator cycle.

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