检索结果-南通市图书馆

Large magnetocaloric effect in metamagnetic HoPdAl

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2012年第2期55卷 445-450页

作者： XU ZhiYi shen baogen State Key Laboratory for Magnetism Institute of PhysicsChinese Academy of SciencesBeijing 100190China

Magnetic properties and magnetocaloric effects(MCEs) of the HoPdAl compounds with the hexagonal ZrNiAl-type and the orthorhombic TiNiSi-type structures are investigated.Both the compounds are found to be antiferromagnet with the Néel temperature TN=12 and 10 K,respectively.A field-induced metamagnetic transition from antiferromagnetic(AFM) state to ferromagnetic(FM) state is observed below TN.For the hexagonal HoPdAl,a small magnetic field can induce an FM-like state due to a weak AFM coupling,which leads to a high saturation magnetization and gives rise to a large MCE around TN.The maximal value of magnetic entropy change(?SM) is-20.6 J/kg K with a refrigerant capacity(RC) value of 386 J/kg for a field change of 0-5 T.For the orthorhombic HoPdAl,the critical field required for metamagnetic transition is estimated to be about 1.5 T,showing a strong AFM coupling.However,the maximal SM value is still-13.7 J/kg K around TN for a field change of 0-5 T.The large reversible SM and considerable RC suggest that HoPdAl may be an appropriate candidate for magnetic refrigerant in a low temperature range.

关键词：磁热效应原子力显微镜高饱和磁化强度钢筋混凝土反铁磁 AFM 磁学性质化合物

Effects of interstitial H and/or C atoms on the magnetic and magnetocaloric properties of La(Fe, Si)_(13)-based compounds

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2013年第12期56卷 2302-2311页

作者： ZHANG Hu HU FengXia SUN JiRong shen baogen Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of Sciences

La(Fe,Si)13-based compounds have been considered as promising candidates for magnetic refrigerants particularly near room temperature.Herein we review recent progress particularly in the study of the effects of interstitial H and/or C atoms on the magnetic and magnetocaloric properties of La(Fe,Si)13compounds.By introducing H and/or C atoms,the Curie temperature TC increases notably with the increase of lattice expansion which makes the Fe 3d band narrow and reduces the overlap of the Fe 3d wave functions.The first-order itinerant-electron metamagnetic transition is conserved and the MCE still remains high after hydrogen absorption.In contrast,the characteristic of magnetic transition varies from first-order to second-order with the increase of C concentration,which leads to remarkable reduction of thermal and magnetic hysteresis.In addition,the introduction of interstitial C atoms promotes the formation of NaZn13-type(1:13)phase in La(Fe,Si)13compounds,and thus reducing the annealing time significantly from 40 days for LaFe11.7Si1.3to a week for LaFe11.7Si1.3C0.2.The pre-occupied interstitial C atoms may depress the rate of hydrogen absorption and release,which is favorable to the accurate control of hydrogen content.It is found that the reduction of particle size would greatly depress the hysteresis loss and improve the hydrogenation process.By the incorporation of both H and C atoms,large MCE without hysteresis loss can be obtained in La(Fe,Si)13compounds around room temperature,for instance,La0.7Pr0.3Fe11.5Si1.5C0.2H1.2exhibits a large|SM|of 22.1 J/(kg·K)at TC=321 K without hysteresis loss for a field change of 0 5 T.

关键词：类化合物原子时 Fe Si 间隙磁性热性质磁滞损耗

A NEW PERMANENT MAGNETIC MATERIALS CRYSTALLIZED FROM AMORPHOUS Co_(84-x)BxZr_(16) ALLOYS

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 1990年第8期7卷 365-368页

作者： shen baogen GUO Huiqun YANG Linyuan ZHAO Jian gao Magnetism Laboratory Institute of PhysicsAcademia SinicaBeijing 100080 CCAST(World Laboratory) Beijing

The crystallization of amorphous Co_(84-x)BxZr_(16) alloys and the influence of heat treatment on its hard magnetic properties are studied.The dependence of B-content on crystallization temperature of the samples is determined from differential scanning calorimetric(DSC)traces.The intrinsic coercivities iHc are found to increase with increasing annealing temperature and go through a mazimum then to lower values.A coercivity of 2.7kOe and an energy product of 4.0MGOe are obtained at room temperature in Co_(82)B_(2)Zr_(16) alloy annealed at 660°C for a short time.These alloys would be expected as an applicable mate rid for permanent magnet.

关键词： alloys alloy

MAGNETIC MOMENT AND CURIE TEMPERATURE OF AMORPHOUS (Fe_(100-x)B_(x))_(88)Nd_(12±ε) ALLOYS

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 1990年第2期7卷 89-92页

作者： shen baogen ZHAO Jiangao ZHANG Zhiying GU Benxi DING Jun HHomburg S.Methfessel Institute of Physics Academia SinicaBeijing 100080 Department of Physics Nanjing UniversityNanjing 210008 Institute fur Experimentalphysik Ⅳ Ruhr-UniversitatBochumFRG

The magnetization curves at 1.5K and Curie temperature of amorphow (Fe_(100-x)B_(x))_(88)Nd_(12±ε) alloys were measured.Their spontaneous magnetizations is explained by a noncollinear structure.The average magnetic moment μ_(Fe) per Fe atom decreases monotonically with increasing x,and becomes more rapid when x>24.The B content dependence of Curie temperature shows a mazimum at x=15.At x<15,the increase of T_(c) with x may be attributed to the indirect exchange interactions between Fe-Fe atoms.

关键词： structure. alloys magnetization

CRYSTALLIZATION OF AMORPHOUS Fe_(62)Co_(15.5)Nd_(4)B_(18.5) ALLOY AND ITS INFLUENCE ON HARD MAGNETIC PROPERTIES

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 1990年第9期7卷 429-432页

作者： shen baogen YANG Linyuan ZHANG Junxian WO Feng NING Taishan ZHAO Jiangao GUO Huiqun ZHAN Wenshan Magnetism Laboratory Institute of PhysicsAcademia SinicaBeijing 100080

Magnetic properties and crystallization of amorphous Fe_(62)Co_(15.5)Nd_(4)B_(18.5) alloy are studied.The Curie temperature of the present sample is 127K higher than that of amorphous Fe_(77.5)Nd_(4)B_(18.5) alloy,but their crystallization temperature is compatible with each other.A coercive field of 2.34kOe,a remanence of 12.3kG and an energy product of 11.6MGOe are obtained at room temperature in the Fe_(62)Co_(15.5)Nd_(4)B_(18.5) alloy annealed at 650°C.The 15.5at.%-Co substitution for Fe results in an increase of about 1l0K in Tc of 2:14:1 phase.

关键词： alloy crystallization amorphous

MAGNETIC MOMENT,CURIE TEMPERATURE AND SPIN WAVE EXCITATION FOR AMORPHOUS Fe_(90-x)Si_xZr_(10) ALLOYS

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1991年第7期4卷 31-36页

作者： shen baogen ZHANG Zhiying GUO Huiqun ZHAO Jiangao

The magnetization curves at 1.5 K and thermomagnetic curves for amorphous Fe_(90-x)Si_xZr_(10)(x=0,4,7 and 10)alloys prepared by the drum spinning technique have been measured with an extracting sample magnetometer.It is obtained that the average magnetic moment,,per magnetic atom and Curie temperature,T_c,in the amorphous FeSiZr alloys increase with increasing Si content.The and T_c are found to be quite small,compared with amorphous FeSiB alloys.This unusual behavior is suggested to be due to the presence of the Fe—Fe antiferromagnetic interactions.The temperature dependence of magnetization at lower temperature is in accordance with Bloch's T^(3/2) law.Calculation shows that the spin wave stiffness constant,D,increases with increasing Si content from 0.37 meV·nm^2 for x=0 to 0.538 meV·nm^2 for x=10.The values ofindicate that the range of the exchange interaction is roughly the mean atomic distance of nearest neighbours.

关键词： amorphous FeSiZr alloys magnetic moment Curie temperature spin wave excitation

Manipulation of topological spin textures in centrosymmetric rare-earth magnets

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2023年第25期156卷 254-260页

作者： Shulan Zuo Kaiming Qiao Ying Zhang Tongyun Zhao Chengbao Jiang baogen shen Key Laboratory of Aerospace Materials and Performance (Ministry of Education) School of Materials Science and EngineeringBeihang UniversityBeijing 100191China School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of SciencesBeijing 100190China Ningbo Institute of Materials Technology & Engineering Chinese Academy of SciencesNingbo 315201China

Topologically protected magnetic skyrmions are expected to be used in the next-generation spintronic devices.Realizing their nucleation and manipulation at room temperature is fundamental for future practical applications.Here,using in situ Lorentz transmission electron microscopy and micromagnetic simulation,we demonstrate that magnetic biskyrmions can spontaneously exist at room temperature in Nd_(1-x) Tb_(x)Co_(5)(x=0.3,0.5)alloys.The spontaneous biskyrmions are controllably obtained over a wide temperature range across room temperature by switching atomic chemical environment.Furthermore,the density of biskyrmions can be tuned by a small magnetic field.High-density biskyrmions are stimulated to form in the thinner region at room temperature by introducing an in-plane magnetic field component.These results provide valuable insights into the manipulation of topological states,which is of great significance to their practical applications.

关键词： Biskyrmions Spin-reorientation transition Manipulation Nd1–TbCo5

柔性衬底提供的机械应变对非晶SmCo薄膜磁性的调控

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

稀有金属材料与工程 2024年第2期53卷 345-349页

作者：梁文会王雨桐苏鉴章明胡凤霞张健刘艳丽任瀚洋王晶沈保根清华大学物理系北京100084 清华大学量子信息前沿科学中心北京100084 中国科学院物理研究所北京100190 中国科学院大学物理科学学院北京100190 松山湖材料实验室广东东莞523808 中国科学院宁波材料技术与工程研究所浙江宁波315201 内蒙古科技大学理学院内蒙古包头014010

将非晶SmCo薄膜沉积在弯曲的柔性聚对苯二甲酸乙二醇酯(PET)衬底上,薄膜厚度范围为10~150nm。薄膜沉积结束后,当PET衬底从凹/凸变平时,非晶SmCo薄膜受到拉伸/压缩应变。结果表明,应变既可以调控SmCo/PET的剩余磁化强度,也可以调控其磁... 详细信息

将非晶SmCo薄膜沉积在弯曲的柔性聚对苯二甲酸乙二醇酯(PET)衬底上,薄膜厚度范围为10~150nm。薄膜沉积结束后,当PET衬底从凹/凸变平时,非晶SmCo薄膜受到拉伸/压缩应变。结果表明,应变既可以调控SmCo/PET的剩余磁化强度,也可以调控其磁滞回线的方形度。与压缩应变相比,拉伸应变对非晶SmCo磁性的调控幅度更大。非晶SmCo薄膜的磁性之所以能够被柔性衬底提供的机械应变所调控是因为非晶SmCo薄膜具有负磁致伸缩特性。当负磁致伸缩效应发生时,拉伸应变会阻碍非晶SmCo薄膜的磁化过程,而压缩应变则会促进非晶SmCo薄膜的磁化过程。非晶SmCo/PET在开发柔性自旋电子器件和柔性微纳电子器件方面具有巨大潜力。

关键词：非晶SmCo薄膜柔性衬底应变磁性

Magnetic Proper ties and Crystallization of Amorphous Fe-Nd-B Alloys at Cons taut B Concentration

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 1993年第10期10卷 620-622页

作者： shen baogen YANG Linyuan ZHAO Jiangao GUO Huiqun State Key Laborti tory of Magnetisjn Institu te of PhysicsAcademia SinicaBeijing 100080

Ma.***.tion,Curie teiiiperti.ture mid crystallization temperature measurements for amorphous(Fe_(1-x)Nd_(x))_(100-y)B_(y) iilloys with y=6,18.5 and 25 have been made.Spon-taneous magnetization shows a monotonic decrease with x,and the noncollinear spin structures have been proposed to expluin the observed results.The composition dependence of Curie tenipertitiire is exphtined by the average niolecular-field model.The substitu lion of siim.ll N<1 for Fc is found to have a strong enha.nccinent of the theriiml stability in amorphous Fe-Nd-B alloys.

关键词： alloys amorphous crystallization