scholarly journals Tuning Magnetocaloric Properties for La-=SUB=-1-x-=/SUB=-Sr-=SUB=-x-=/SUB=-CoO-=SUB=-3-=/SUB=-

2021 ◽  
Vol 63 (10) ◽  
pp. 1551
Author(s):  
E.M. Ahmed ◽  
H.R. Alamri ◽  
S.M. Elghnam ◽  
O. Eldarawi ◽  
T.E. Tawfik ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Magnetocaloric Effect ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Paramagnetic State ◽  
Magnetic Entropy ◽  
Magnetocaloric Properties ◽  
Low Magnetic Field

Low magnetic field magnetocaloric (MC) properties of La1-xSrxCoO3 (x=0.3 and 0.5) near phase transition from a ferromagnetic to a paramagnetic state were investigated. It is shown that the change of Sr content allows MC effect in La1-xSrxCoO3 to be tunable, which is more practical for construction of MC refrigeration. MC properties of the x=0.5 sample are significantly greater than that of the x=0.3 one. Furthermore, the results show that MC properties of La1-xSrxCoO3 samples are significantly larger, and comparable with some MC properties of many materials like Gd1-xCaxBaCo2O5.5 and Ge0.95Mn0.05. Keywords: magnetocaloric effect, La1-xSrxCoO3, magnetic entropy change.

The Magnetocaloric Effect and Magnetic Transitions in Hydride Compounds: GdNiH3.2 and TbNiH3.4

2015 ◽  
Vol 233-234 ◽  
pp. 243-246
Author(s):  
A.I. Smarzhevskaya ◽  
S.A. Nikitin ◽  
Viktor N. Verbetsky ◽  
Wacław Iwasieczko ◽  
Alexey N. Golovanov
Keyword(s):  
Magnetocaloric Effect ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Magnetic Entropy ◽  
Magnetic Transitions ◽  
Isothermal Magnetization ◽  
Magnetocaloric Properties ◽  
Magnetization Data

The paper presents the investigation of GdNiH3.2 and TbNiH3.4 hydrides magnetic transitions and magnetocaloric properties. The isothermal magnetization data in the fields up to 5T are obtained for GdNi and TbNi compounds and their hydrides and the values of magnetic entropy change are calculated. The maximum values of magnetic entropy change ΔSM in GdNiH3.2 and TbNiH3.4 are extremely large. It is shown that the hydrogenation shifts ΔSM(T) maximum to lower temperatures.

MAGNETIC ENTROPY CHANGE IN A TWO-DIMENSIONAL ANTIFERROMAGNETIC SQUARE LATTICE

2006 ◽  
Vol 20 (18) ◽  
pp. 2527-2536
Author(s):  
H. GENCER
Keyword(s):  
Magnetocaloric Effect ◽  
Magnetic Entropy Change ◽  
Nearest Neighbor ◽  
Entropy Change ◽  
Square Lattice ◽  
Magnetic Entropy ◽  
Maximum Value ◽  
Magnetocaloric Properties ◽  
State Present ◽  
Entropy Variation

In this study, we investigate magnetic entropy variation and magnetocaloric properties as a function of frustration by considering a spin-1/2 antiferromagnetic Heisenberg model on a square lattice with nearest (J1) and next-nearest neighbor exchange interaction (J2). We show that the degree of frustration in the square lattice increases with α=J2/J1. While the square lattice is unfrustrated for α = 0, it becomes fully frustrated for α=0.5. Numerical results show that the entropy of the square lattice approaches zero for the unfrustrated case at T=1 K. In contrast, finite entropy can survive in the frustrated case at the same temperature. We also calculate the magnetic entropy change (ΔSm) in the square lattice and show that the maximum value of ΔSm increases with increasing α. These results indicate that the magnetic entropy change and consequently the magnetocaloric effect can be enhanced by increasing the degree of frustration. We conclude that the enhanced magnetocaloric effect is related to quantum fluctuations and disordered ground state present in the frustrated square lattice.

The Influence of the Purity of Gd on the Magnetocaloric Effect in Gd5Si2-XGe2-XZn2x Alloys

2011 ◽  
Vol 685 ◽  
pp. 311-315
Author(s):  
Zhi Zeng ◽  
Xue Zhen Wang ◽  
Jian Huang ◽  
Jie Xiang ◽  
Xue Ling Hou
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetocaloric Effect ◽  
Curie Point ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Magnetic Entropy ◽  
Field Change ◽  
Magnetic Field Change ◽  
Giant Magnetocaloric Effect

Gd5Si2Ge2-based alloys can exhibit a giant magnetocaloric effect (GMCE) which gives them the potential use in the cooling technologies[1].Through this studies, it can be found that the purity of Gd had a great impact on the magnetocaloric effect in Gd5Si2-xGe2-xZn2x alloys. When 3N Gd used and 2x=0.01, Gd5Si2-xGe2-xZn2x around the curie point of 280k get the maximum magnetic entropy change of 14.0 J/(Kg.K) under the external magnetic field change from 0 to 1T, but when 2N Gd used and 2x=0.05, Gd5Si2-xGe2-xZn2x around the curie point of 284.2k under the external magnetic field change 1T get the maximum magnetic entropy change 6.65 J/(Kg.K).

Study of Magnetocaloric Properties of Ni-Mn-X (X = Ga, In) Heusler Alloys by Monte Carlo Technique

2009 ◽  
Vol 1200 ◽  
Author(s):  
Vasiliy Buchelnikov ◽  
Vladimir Sokolovskiy ◽  
Sergey Taskaev ◽  
Peter Entel
Keyword(s):  
Experimental Data ◽  
Phase Transition ◽  
Monte Carlo ◽  
Magnetic Entropy Change ◽  
Heusler Alloys ◽  
Entropy Change ◽  
Magnetic Contribution ◽  
Magnetic Entropy ◽  
First Order ◽  
Magnetocaloric Properties

AbstractTwo theoretical Monte Carlo models have been presented for description of the positive and negative magnetocaloric effects of Heusler Ni-Mn-X (X = Ga, In) alloys undergoing first order coupled magnetostructural phase transition. For both models all quantities such as temperature dependence of the magnetic contribution to the total specific heat, magnetization and isothermal magnetic entropy change are in qualitative agreement with the available experimental data.

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.

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.

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.

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.

Room Temperature Magnetocaloric Effect of the Cox(MnSb)1-x Compounds

2013 ◽  
Vol 683 ◽  
pp. 56-59 ◽  
Author(s):  
Jian Hua Lin ◽  
Shan Dong Li ◽  
Li Li Wang ◽  
Jie Qiu ◽  
Zhi Yi Cai ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetocaloric Effect ◽  
Room Temperature ◽  
Magnetic Entropy Change ◽  
Magnetic Hysteresis ◽  
Entropy Change ◽  
Magnetic Entropy ◽  
Thermal Lag ◽  
Magnetocaloric Materials ◽  
Curie Temperature Tc

The room-temperature magnetocaloric effect (MCE) of Cox(MnSb)1-x (x=0.07, 0.15, 0.24) alloys has been investigated. It is revealed that the Curie temperature TC and the magnetic entropy change ΔSM are sensitive to the Co content x. When x=0.15, the MCE of Co0.15(MnSb)0.85 alloy is optimal with ΔSM=1.8 J/kg.K at 324 K under an applied magnetic field of 3 T. A second-order phase transformation occurs around TC, and the magnetic hysteresis loss thermal lag is negligible. These features demonstrate that Co0.15(MnSb)0.85 alloy is a promising room-temperature magnetocaloric materials.

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