Remarkable LnIII3FeIII2 clusters with magnetocaloric effect and slow magnetic relaxation

2015 ◽  
Vol 44 (2) ◽  
pp. 468-471 ◽  
Author(s):  
Han Li ◽  
Wei Shi ◽  
Zheng Niu ◽  
Jing-Min Zhou ◽  
Gang Xiong ◽  
...  
Keyword(s):  
Magnetocaloric Effect ◽  
Magnetic Relaxation ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Magnetic Entropy ◽  
Slow Magnetic Relaxation

Two 3d–4f clusters were reported: Gd3Fe2 possesses significant magnetic entropy change and slow magnetic relaxation is observed in Dy3Fe2.

A series of new octanuclear Ln8 clusters: magnetic studies reveal a significant cryogenic magnetocaloric effect and slow magnetic relaxation

2019 ◽  
Vol 43 (3) ◽  
pp. 1617-1625 ◽  
Author(s):  
Ling-Fei Li ◽  
Wei-Wei Kuang ◽  
Yi-Ming Li ◽  
Li-Li Zhu ◽  
Yun Xu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetocaloric Effect ◽  
Direct Current ◽  
Magnetic Relaxation ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Magnetic Entropy ◽  
Magnetic Studies ◽  
Slow Magnetic Relaxation ◽  
Current Magnetic Field

A series of new octanuclear Ln8 clusters. Magnetically, Gd8 exhibited a significant magnetocaloric effect and a magnetic entropy change is 32.49 J K−1 kg−1 for a field of 7 T at 2 K, while Dy8 exhibited a frequency dependent slow relaxation of magnetization at a zero applied direct current magnetic field.

Large magnetic entropy change at cryogenic temperature in rare earth HoN nanoparticles

RSC Advances ◽  
2016 ◽  
Vol 6 (79) ◽  
pp. 75562-75569 ◽  
Author(s):  
K. P. Shinde ◽  
S. H. Jang ◽  
M. Ranot ◽  
B. B. Sinha ◽  
J. W. Kim ◽  
...  
Keyword(s):  
Rare Earth ◽  
Low Temperature ◽  
Magnetocaloric Effect ◽  
Cryogenic Temperature ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Environmental Problems ◽  
Magnetic Refrigeration ◽  
Magnetic Entropy ◽  
Alternative Technology

The most extensive cooling techniques based on gases have faced environmental problems. The magnetic refrigeration is an alternative technology based on magnetocaloric effect. HoN nanoparticles are good refrigerant material at low temperature.

Refrigerant Capacity and Magnetocaloric Effect on LaFe11.1Co0.8Si1.1BX Alloys

2011 ◽  
Vol 84-85 ◽  
pp. 667-670
Author(s):  
Guo Qiu Xie
Keyword(s):  
Magnetocaloric Effect ◽  
Room Temperature ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Magnetic Entropy ◽  
Field Change ◽  
Refrigerant Capacity ◽  
Structure Phase ◽  
Magnetic Field Change ◽  
Cubic Structure

In this paper, we report on the structure, magnetic properties and magnetocaloric effect in NaZn13-type LaFe11.1Co0.8Si1.1Bxalloys close to room temperature. The stable NaZn13cubic structure phase (space group isFm-3c) can easily obtained by annealing at 1080 °C for 225 hours. The maximal values of magnetic entropy change for LaFe11.1Co0.8Si1.1Bx(x=0.2, 0.25) were found to be 5.3 and 5.9 J/kg K at Curie temperature for a magnetic field change in 0-1.5 T, respectively. The calculated refrigerant capacity for a field change in 0–1.5 T is about 147 and 107 J/kg K, for LaFe11.1Co0.8Si1.1B0.2and LaFe11.1Co0.8Si1.1B0.25respectively, which is as larger as those of Gd(99.3%) alloy

scholarly journals Modeling the Maximum Magnetic Entropy Change of Doped Manganite Using a Grid Search-Based Extreme Learning Machine and Hybrid Gravitational Search-Based Support Vector Regression

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 310 ◽  
Author(s):  
Sami M. Ibn Shamsah ◽  
Taoreed O. Owolabi
Keyword(s):  
Magnetocaloric Effect ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Support Vector ◽  
Grid Search ◽  
Magnetic Entropy ◽  
Ionic Model ◽  
Crystal Model ◽  
Learning Machine ◽  
Better Than

The thermal response of a magnetic solid to an applied magnetic field constitutes magnetocaloric effect. The maximum magnetic entropy change (MMEC) is one of the quantitative parameters characterizing this effect, while the magnetic solids exhibiting magnetocaloric effect have great potential in magnetic refrigeration technology as they offer a green solution to the known pollutant-based refrigerants. In order to determine the MMEC of doped manganite and the influence of dopants on the magnetocaloric effect of doped manganite compounds, this work developed a grid search (GS)-based extreme learning machine (ELM) and hybrid gravitational search algorithm (GSA)-based support vector regression (SVR) for estimating the MMEC of doped manganite compounds using ionic radii and crystal lattice parameters as descriptors. Based on the root-mean-square error (RMSE), the developed GSA-SVR-radii model performs better than the existing genetic algorithm (GA)-SVR-ionic model in the literature by 27.09%, while the developed GSA-SVR-crystal model performs better than the existing GA-SVR-lattice model in the literature by 38.34%. Similarly, the developed ELM-GS-crystal model performs better than the existing GA-SVR-ionic model with a performance enhancement of 14.39% and 20.65% using the mean absolute error (MAE) and RMSE, respectively, as performance measuring parameters. The developed models also perform better than the existing models using correlation coefficient as the performance measuring parameter when validated with experimentally measured MMEC. The superior performance of the present models coupled with easy accessibility of the descriptors definitely will facilitate the synthesis of doped manganite compounds with a high magnetocaloric effect without experimental stress.

scholarly journals Magnetorefrigeration capability of a gadolinium(iii) coordination polymer containing trimesic acid: a correlation between the isothermal magnetic entropy change and the gadolinium content

RSC Advances ◽  
2017 ◽  
Vol 7 (49) ◽  
pp. 30763-30769 ◽  
Author(s):  
Radovan Herchel ◽  
Kamil Kotrle ◽  
Zdeněk Trávníček
Keyword(s):  
Coordination Polymer ◽  
Magnetocaloric Effect ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Magnetic Entropy ◽  
General Correlation ◽  
Trimesic Acid

A general correlation for Gd(iii) complexes showing the magnetocaloric effect was proposed.

MAGNETOCALORIC EFFECT IN THE INTERMETALLIC COMPOUND Gd3Ni8Al

2012 ◽  
Vol 26 (25) ◽  
pp. 1250167 ◽  
Author(s):  
M. X. WANG ◽  
H. FU ◽  
Q. ZHENG ◽  
J. TANG
Keyword(s):  
Intermetallic Compound ◽  
Magnetocaloric Effect ◽  
Single Phase ◽  
Magnetic Entropy Change ◽  
Magnetic Measurements ◽  
Entropy Change ◽  
Magnetic Entropy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Refrigerant Capacity

The magnetic properties and magnetocaloric effect of the polycrystalline Gd 3 Ni 8 Al intermetallic compound are studied in this paper. Powder X-ray diffraction shows that the alloy is CeNi 3-type single-phase structure. The magnetic measurements indicate that the compound is ferromagnetic and undergoes a second-order phase transition at 62 K. The maximum of magnetic entropy change reaches 11 J/kg K for the field change from 0 to 50 kOe and the refrigerant capacity of the titled compound is found to be 4.8×102 J/kg.

THE VARIATION OF EXCHANGE CONSTANT AND MAGNETOCALORIC EFFECT IN LaFe13-xSix (x = 1.6, 1.9 AND 2.2) COMPOUNDS

2011 ◽  
Vol 25 (25) ◽  
pp. 3303-3313 ◽  
Author(s):  
T. IZGI ◽  
V. S. KOLAT ◽  
H. GENCER ◽  
S. ATALAY
Keyword(s):  
Magnetocaloric Effect ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Wave Dispersion ◽  
Lattice Parameter ◽  
Exchange Constant ◽  
Magnetic Entropy ◽  
Arc Melting ◽  
Exchange Constants ◽  
Si Content

In this work, we present the variation of exchange constant (J exc ) and magnetocaloric effect (MCE) in LaFe 13-x Si x (x = 1.6, 1.9 and 2.2) compounds. NaZn 13-type LaFe 13-x Si x intermetallic compounds were prepared by arc melting in an atmosphere of highly pure argon gas. X-ray results indicated a slight decrease of lattice parameter with increasing Si content. The maximum magnetic entropy change of the LaFe 13-x Si x (x = 1.6, 1.9 and 2.2) samples decreases with increasing Si contents. Also, the magnetic entropy change was calculated theoretically at various magnetic fields and compared with experimental data. The spin-wave dispersion coefficients (D) and exchange constants (J exc ) were calculated for the fist time for these samples. It was found that D and J exc increase with increasing Si content.

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 Features of Magnetocaloric Effect in Er(Co-Fe)2 Laves Phases

2016 ◽  
Vol 1 (1) ◽  
pp. 5 ◽  
Author(s):  
M.S. Anikin ◽  
E.N. Tarasov ◽  
N.V. Kudrevatykh ◽  
M.A. Semkin ◽  
A.S. Volegov ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Phase Composition ◽  
Magnetocaloric Effect ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Magnetic Entropy ◽  
Concentration Increase ◽  
Laves Phases ◽  
X Ray ◽  
Temperature Range

<p>In this work the results of measurements of heat capacity (C<sub>P</sub>) and magnetocaloric effect (MCE) in Er(Co<sub>1-</sub><sub>х</sub>Fe<sub>х</sub>)<sub>2</sub> system in the concentration range 0.07 ≤ x ≤ 0.80 are presented. Phase composition was controlled by X-ray difraction analysis. Heat capacity was measured in the temperature range 77-320 K. MCE has been studied within the temperature range 5-670 K in magnetic fields up to 70 kOe. It was found that Fe concentration increase caused the table-like (plateau) MCE temperature dependence for both magnetic entropy change date and direct ∆T-effect measurements independently on Fe concentration. The possible reasons of such behavior are discussed.</p>

A triangular [Mn3] cluster-based ferrimagnet with significant magnetic entropy change

2015 ◽  
Vol 3 (14) ◽  
pp. 3494-3499 ◽  
Author(s):  
Huan-Cheng Hu ◽  
Chun-Shuai Cao ◽  
Yang Yang ◽  
Peng Cheng ◽  
Bin Zhao
Keyword(s):  
Magnetocaloric Effect ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Magnetic Entropy

A triangular [Mn3] cluster-based ferrimagnet [Na2Mn3(SO4)3(μ3-OH)2(μ2-OH2)2]n exhibits a significant magnetocaloric effect (−ΔSm = 14.4 J kg−1 K−1) at 13.5 K.

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