POLYHEDRON
·
2022
·
IF 2.975
Na Qiao,Xiao-Xiao Li,Ying Chen,Xiao-Yan Xin,Chen Yang,Shan-Shan Dong,Yan-Zi Wang,Xing-Jin Li,Yu-Peng Hua,Wen-Min Wang
Three dinuclear Ln 2 compounds, [Ln 2 (dbm) 4 (L - ) 2 ]·4CH 3 CN (Ln = Gd ( 1 ), Tb ( 2 ), Dy ( 3 ), HL = (E)-N'-(2-hydroxybenzylidene)benzohydrazide and dbm = dibenzoylmethane), have been obtained by a solvent evaporation method. The structural analyses indicate that the three Ln 2 compounds (Gd 2 , Tb 2 and Dy 2 ) are isostructural with a Ln 2 O 2 center. Magnetic investigations show the presence of magnetic refrigeration in the Gd-based compound with a -ΔS m value of 17.62 J kg −1 K −1 ( T = 2.0 K and Δ H = 7.0 T); for compound 3 , however, single-molecular magnet behavior (SMM) was observed ( U eff /k B = 0.84 K and τ 0 = 1.08 × 10 −5 s).
研究领域:
化学
·
材料科学
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DOI
高影响因子
Journal of the American Chemical Society
·
2024
·
IF 14.4
Bingjie Wang,Xinyang Liu,Fengxia Hu,Jian-tao Wang,Junsen Xiang,Peijie Sun,Jing Wang,Jirong Sun,Tongyun Zhao,Zhaojun Mo,Jun Shen,Yunzhong Chen,Qingzhen Huang,Baogen Shen
Adiabatic demagnetization refrigeration (ADR) based on the magnetocaloric effect (MCE) is a promising technique to achieve cryogenic temperature. However, magnetic entropy change (ΔSM), the driving force of ADR, remains far below theoretical −ΔSM = nRln(2J + 1)/MW for most magnetic refrigerants. Here, we report giant MCE in orthorhombic EuCl2, where a ferromagnetic ground state with excellent single-ion behavior of Eu2+ and free spins has been demonstrated by combining ab initio calculations with Brillouin function analysis and magnetic measurements. Consequently, a record-high −ΔSM ∼ 74.6 J·kg–1·K–1 (1.8 K) at 5 T was experimentally achieved, approaching 96% of the theoretical limit (77.5 J·kg–1·K–1). At a lower field of 1 T, EuCl2 also achieves the highest-ever record of −ΔSM ∼ 36.8 J·kg–1·K–1. Further, direct quasi-adiabatic demagnetization measurements demonstrate that its large −ΔSM allows EuCl2 to maintain a long holding time at sub-Kelvin temperature (∼346 mK), surpassing all previously reported materials. These superior magnetocaloric performances position EuCl2 as an attractive cryogenic refrigerant.
研究领域:
材料科学
·
物理学
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DOI
PubMed
高影响因子
AIP Advances
·
2024
·Vol. 14
·期 5
·
IF 1.4
Liu Peng,Ren Weijun,Guo Qing,Zhang Zhao,Zhao Xueting,Zhang Zhidong,Dai Wei,Li Bing
Cryogenic refrigeration technology based on magnetocaloric effects plays a critical role in a variety of technological applications. In this paper, we report the cryogenic magnetocaloric effects of a series of sodium-rare earth fluoride samples (Ln = Gd, Tb, Dy, Ho, Er, Tm, Yb) synthesized by the solid-state reaction method. These compounds all crystallize in a hexagonal crystal structure. Down to 2 K, no magnetic ordering was detected, while all compounds show negative Curie–Weiss temperatures indicative of strong antiferromagnetic coupling. Magnetic fields effectively suppress the magnetic fluctuations, leading to a maximum magnetic entropy change of −56 J kg −1 K −1 in NaGdF 4 at the magnetic field change from 0 to 50 kOe. These series of compounds are potentially excellent magnetic refrigerants at low temperatures.
研究领域:
物理学
·
材料科学
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Canglong Li,Xuechi Lu,Xinshuai Niu,Boyuan Zou,Yao Zhao,Xuanjie Li,Yang Lu,Yongsong Luo
The magnetic refrigeration is achieved through the magnetocaloric effect of a magnetic system, which is considered a promising technology for achieving the required low temperatures in industry, daily life, and scientific research. This work experimentally investigates the magnetic behavior and magnetocaloric performance of Ho 2 CoMn 1- x Ti x O 6 (0 ≤ x ≤ 1) double perovskites. The experimental results reveal that a paramagnetic →ferromagnetic transition characterized by a sharp increase in magnetization is suppressed due to decoupling action of Ti 4+ with 3 d 0 spin configuration. As a result, the transition temperature T C reduces monotonically from 75 K at x = 0–37 K at x = 0.6, and no obvious ferromagnetic transition is identified at x = 0.8–1 due to the lack of Co 2+ –Mn 4+ interactions at so high Ti 4+ substitution concentration. In addition, the magnetocaloric effect is investigated by measuring the isothermal initial magnetization from 4 K to a temperature far above T C . The maximum magnetic entropy ( − Δ S M max ) under Δ H = 6 T does not exhibit significant variation from x = 0 (11.1 J kg −1 K −1 ) to 0.6 (11.5 J kg −1 K −1 ), while it increases noticeably from x = 0.8 (13.9 J kg −1 K −1 ) to 1 (17.2 J kg −1 K −1 ). The present work indicates that the cryogenic magnetocaloric effect can be improved by dilution effect of nonmagnetic ions.
研究领域:
材料科学
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凝聚态物理
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应用物理
·
磁性材料
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DOI
高影响因子
JOURNAL OF CRYSTAL GROWTH
·
2024
·
IF 1.7
Yuwei Chen,Wang Liu,Zuhua Chen,Zhenxing Li,Jun Shen,Heng Tu,Guochun Zhang
High-quality Na 2 Gd 2 (BO 3 ) 2 O crystals have been successfully grown using the top-seeded solution growth method (TSSG), employing a Na 2 O - NaF - B 2 O 3 flux system with optimal molar ratios of Na 2 Gd 2 (BO 3 ) 2 O : Na 2 CO 3 : NaF : H 3 BO 3 = 1:2:6:4. The magnetic and magnetocaloric properties were investigated including magnetic susceptibility ( χ ), magnetization ( M ), and isothermal magnetic entropy change ( −ΔS m ) measurements. Na 2 Gd 2 (BO 3 ) 2 O exhibits a large magnetocaloric effect with a maximum − ΔS m of 41.6 J·kg −1 ·K −1 at 2 K and 7 T, which is higher than that of commercial Gd 3 Ga 5 O 12 (GGG, −ΔS m = 38.4 J·kg −1 ·K −1 at 2 K and 7 T) and most other Gd 3+ -based borates, showing the potential application in the field of magnetic refrigeration.
研究领域:
材料科学
·
物理学
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DOI
高影响因子
POLYHEDRON
·
2021
·
IF 3.052
Qin Wang,Hui-Min Gao,Wen-Juan Xue,Kai-Yang Chen,Quan Zhang,Min Huang,Rui-Feng Wang,Wen-Liang Fan,Yu-Peng Hua,Ming Fang
Four new acyloxy bridged Ln III 2 compounds [Ln 2 (L) 2 (acac) 2 (EtOH) 2 ] (Ln(III) = Gd ( 1 ), Tb ( 2 ), Dy ( 3 ), and Ho ( 4 ), Hacac = acetylacetone, and H 2 L = pyridine-2-carboxylic acid (3-ethoxy-2-hydroxy-benzylidene)-hydrazide) have been prepared by a polydentate Schiff base ligand under solvothermal condition. The single-crystal X-ray structure study reveals that 1 – 4 are isostructural and contain a parallelogram Ln 2 O 2 core. Magnetic study reveals that antiferromagnetic interaction exists in compound 1 . More importantly, compound 1 displays well cryogenic magnetic refrigeration property (−Δ S m = 28.2 J kg −1 K −1 , T = 2.0 K and Δ H = 70 kOe); while compound 3 exhibits evident single-molecule magnet behavior under zero-field condition (Δ E / k B = 26.8 K, τ 0 = 1.05 × 10 −7 s).
研究领域:
无机化学
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材料科学
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产品关联
DOI
高影响因子
DALTON TRANSACTIONS
·
2021
·Vol. 50
·期 37
·12931-12943
·
IF 4.39
Wen-Min Wang,Zhi-Lei Wu,Jian-Zhong Cui
A series of tetranuclear lanthanide-based clusters [Ln4(dbm)6(L)2(CH3OH)4]·2CH3OH (Ln(III) = Gd (1), Dy (2), and Ho (3); H3L = 2-[(2-(hydroxyimino)propanehydrazide)methyl]-2,3-dihydroxybenzaldehyde, Hdbm = dibenzoylmethane) and octanuclear lanthanide-based clusters [Ln8(HL)10(CH3O)4(CH3OH)2]·6CH3OH (Ln(III) = Gd (4), Dy (5)) were assembled using a polydentate Schiff-base ligand H3L and two different β-diketone salts via a solvothermal method, and their structures and magnetic properties have been characterized. Interestingly, β-diketones play an important role in assembling and affecting the structures of Ln4 to Ln8 clusters. This is the first use of β-diketone to affect the structures of polynuclear Ln(III)-based clusters from linear-shaped Ln4 clusters to Ln8 clusters. Magnetic studies revealed that antiferromagnetic interactions exist in clusters 1-Gd4 and 4-Gd8. More importantly, clusters 1-Gd4 and 4-Gd8 display significant cryogenic magnetic refrigeration properties (−ΔSm = 24.88 J kg−1 K−1 for 1-Gd4 and −ΔSm = 32.52 J kg−1 K−1 for 4-Gd8); the results show that cluster 4-Gd8 exhibits a larger magnetocaloric effect than 1-Gd4. Cluster 2-Dy4 shows remarkable single-molecule magnet (SMM) behavior (ΔE/kB = 67.5 K and τ0 = 3.06 × 10−7 s) under a zero dc field, and 5-Dy8 exhibits a field-induced SMM-like behavior (ΔE/kB = 39.83 K and τ0 = 2.12 × 10−7 s) under a 5000 Oe dc field.
研究领域:
无机化学
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材料科学
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物理化学
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产品关联
DOI
PubMed
高影响因子
DALTON TRANSACTIONS
·
2025
·
IF 3.3
Xuetong He,Lu Tian,Jianjian Gong,Zhaojun Mo,Xinqiang Gao,Guodong Liu
The global helium shortage and escalating costs in cryogenic engineering have intensified demands for helium-free refrigeration technologies. Adiabatic demagnetization refrigeration (ADR) based on the magnetocaloric effect (MCE) presents a viable solution, with its efficacy fundamentally dependent on advanced magnetocaloric materials. Here we present the successful synthesis of a novel gadolinium garnet Gd3Te2Li3O12 through solid-state reaction, which crystallizes in the cubic Ia-3d space group. The integration of magnetic characterization results with density functional theory (DFT) calculations establishes Gd3Te2Li3O12 as an antiferromagnetic compound exhibiting ultra-low magnetic ordering below 0.4 K. A comprehensive evaluation of the sub-kelvin magnetocaloric parameters demonstrates advantageous characteristics compared to commercial gadolinium gallium garnet (GGG) benchmarks, featuring both reduced magnetic ordering temperature and optimized entropy variation in the sub-Kelvin regime. These metrics position Gd3Te2Li3O12 as a prime candidate for sub-Kelvin ADR systems, while the observed geometrically frustrated magnetic sublattice configuration suggests new design principles for next generation magnetocaloric materials.
研究领域:
材料科学
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低温物理
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凝聚态物理
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产品关联
DOI
PubMed
高影响因子
CRYOGENICS
·
2022
·
IF 2.134
Yuwei Chen,Wang Liu,Jingcheng Feng,Ruixin Guo,Feidi Fan,Jun Shen,Guochun Zhang,Heng Tu
A series of lanthanide-rich oxyborates LiLn 6 O 5 (BO 3 ) 3 (LLnOB, Ln = Gd, Tb, Dy, and Ho) have been synthesized using high temperature solid state method. Their magnetic and magnetocaloric properties were investigated upon magnetic susceptibility ( χ ), magnetization ( M ), and isothermal magnetic entropy change ( −ΔS m ) measurements. The maximum − ΔS m, max of LiGd 6 O 5 (BO 3 ) 3 is 44.7 J kg −1 K −1 at 4 K and Δμ 0 H = 9 T, which is higher than the one of commercial Gd 3 Ga 5 O 12 (GGG, −ΔS m, max = 41.8 J kg −1 K −1 at 2 K for Δμ 0 H = 9 T). For LiHo 6 O 5 (BO 3 ) 3 , −ΔS m, max is 14.12 J kg −1 K −1 at 3 K and Δμ 0 H = 2 T, which is also larger than that of Ho 3 Ga 5 O 12 (HoGG, − ΔS m, max = 4.38 J kg −1 K −1 at 2 K for Δμ 0 H = 2 T) and Dy 3 Ga 5 O 12 (DGG, − ΔS m, max = 11.0 J kg −1 K −1 at 2 K for Δμ 0 H = 2 T). These results indicate that LiGd 6 O 5 (BO 3 ) 3 and LiHo 6 O 5 (BO 3 ) 3 may be competitive candidates for applications as magnetic refrigerants. Moreover, thermal stability, infrared spectrum (IR), and ultraviolet–visible-near-infrared diffuse reflectance spectrum (UV–Vis-NIR) were carried out to characterize the title compounds.
研究领域:
材料科学
·
物理学
·
化学
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DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Huicai Xie,Quanyi Liu,Xiaohua Luo,Shengcan Ma,Xinqiang Gao,Zhenxing Li,Zhaojun Mo,Jun Shen
For more practical applications, research on magnetic refrigeration has been gradually focused on developing refrigerants with large magnetocaloric effect (MCE) under low magnetic fields (≤2 T). EuTiO 3 exhibits considerable low-field MCE near ordering temperature, meanwhile the magnetic switch from antiferromagnetic to ferromagnetic (AFM-FM) in it provides the feasibility of improving the magnetocaloric performance. In this study, a series of Eu(Ti,Nb,M)O 3 (M=Cu or Zn) compounds were synthesized, and the crystal structure, magnetic properties together with cryogenic MCEs were investigated in detail. The co-substitution contributes to an FM coupling domination in all the compounds. Besides, significantly enhanced and giant low-field MCEs were detected in these compounds. Under the field change of 1 T, all the samples possess remarkable magnetic entropy change (>15 J·kg -1 ·K -1 ) around 5 K without hysteresis. The corresponding refrigerating capacities are calculated to be 68.0, 72.6, 76.0, and 69.6 J·kg -1 , respectively, exhibiting an increase of 149–178% than EuTiO 3 . The outstanding magnetocaloric performances make the Eu(Ti,Nb,M)O 3 (M=Cu or Zn) compounds competitive candidates for cryogenic magnetic refrigeration.
研究领域:
材料科学
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凝聚态物理
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功能材料
·
低温工程
·
磁学
✓ 已验证
DOI
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2023
·
IF 3.3
Yuwei Chen,Jingcheng Feng,Feidi Fan,Jun Shen,Guochun Zhang,Heng Tu
Three new transition-metal-based borate crystals, Li 5 MgSrMB 12 O 24 (M = Cr, Ni) and Li 5 ZnSrNiB 12 O 24 , were obtained using the high temperature solution method. Their structures were determined by the single crystal X-ray diffraction, which crystallize in the trigonal R 3 ¯ space group. The [B 3 O 11 ] groups in the structures lead to the long distance between two nearest magnetic ions, which can reduce the interaction of adjacent magnetic centers. The magnetic properties and thermal stabilities of the title compounds were also investigated. The results indicated that Li 5 MgSrCrB 12 O 24 has stable chemical-physical properties and its maximum –ΔS m value of 14.33 J kg −1 ·K −1 at 2 K for Δμ 0 H = 9 T reaching 88.6% of the theoretical paramagnetic limit, suggesting its potential application on the magnetic refrigeration.
研究领域:
材料科学
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固体化学
·
磁学
·
热力学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·Vol. 51
·期 25
·46918-46925
·
IF 5.6
Quanyi Liu,Junfeng Wang,Lu Tian,Jiaxin Jiang,Qi Fu,Huicai Xie,Xinqi Zheng,Zhaojun Mo
Cryogenic refrigeration plays a key strategic role in many scientific frontiers and engineering technology fields. Magnetic refrigeration has the advantages of intrinsically high efficiency and independence from liquid helium, and has attracted great attention in cryogenic refrigeration. In recent years, larger low-field magnetocaloric effect (MCE) at lower temperatures have been a continuing pursuit of materials researchers in related fields. Herein, an orthorhombic-structured EuZrO 3 polycrystal and two derivatives were prepared via a modified solid-phase reaction approach. Experimental results reveal that EuZrO 3 undergoes a paramagnetic-antiferromagnetic phase transition near the liquid helium temperature. When part of Zr element is substituted by Nb or Ta, the phase transition temperature decreases to 3.8 K, below which the compounds still behave antiferromagnetically ordered. However, the MCEs of the compounds at low temperatures and low fields are significantly enhanced, which may be attributed to the enhanced ferromagnetic interaction. The maximum magnetic entropy change ( − Δ S M max ) and refrigeration capacity of EuZr 0.875 Nb 0.125 O 3 and EuZr 0.875 Ta 0.125 O 3 are both improved by more than 20 % over EuZrO 3 under magnetic field change of 0–1 T. It is worth noting that the magnetic entropy change values at 2.5 K are improved by a factor of more than four over that of EuZrO 3 for these two derivative compounds.
研究领域:
材料科学
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凝聚态物理
·
功能陶瓷
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低温工程
·
磁制冷
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）