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1.
机械合金化的原理及在磁性材料研究中的应用   总被引:14,自引:0,他引:14  
居毅  李宗权 《功能材料》2002,33(1):12-14,18
介绍了机械合金化的原理和描述机械合金化过程的理论模型。综述了机械合金化在磁性材料研究中的应用,并对目前研究中的存在的问题及发展前景进行了分析。  相似文献   

2.
翁孟超  陈磊  杨志强 《材料导报》2007,21(6):112-115
阐述了磁性材料的重要性及其超快过程研究中存在的问题,对飞秒抽运探测(Pump-probe)技术的试验方法和原理进行了论述.介绍了飞秒抽运探测技术对磁性材料中磁化动力学过程的研究现状,以及抽运探测在磁性材料研究中的新发展--对磁致伸缩材料中的磁化动力学过程研究、对材料复介电常数的测定和光学探针技术的引入,为磁性材料的应用和磁化动力学研究提供了新的方向.  相似文献   

3.
本文简述了一些主要磁参数和温度的关系。介绍了研究高温磁性材料的来由。概述了有关高温电器、电子设备对磁性材料的要求。最后介绍了迄今为止高温磁性材料的研究工作的结果。  相似文献   

4.
块体纳米磁性材料研究进展   总被引:5,自引:1,他引:4  
介绍了块体纳米磁性材料的形成机理以及制备方法与工艺,分别对软磁和永磁两体系中纳米磁性材料与传统磁性材料的磁性能进行了对比,并介绍了最新的几种纳米磁性材料体系。  相似文献   

5.
热疗用磁性材料研究进展   总被引:1,自引:0,他引:1  
在介绍热疗用磁性材料研究概况的基础上,对其研究进展进行了详细综述,重点介绍了Fe3O4和γ-Fe2O3两类材料的制备方法、产热能力研究以及动物实验等方面的内容,最后对热疗用磁性材料的发展前景进行了展望.  相似文献   

6.
简要地介绍了磁性材料的进展,同时对磁性材料的分类提出了除按磁滞回线分类外还可以按交叉效应进行分类的观点。调控自旋将成为新世纪重要的研究领域。  相似文献   

7.
恶性肿瘤局部热疗用纳米磁性材料   总被引:1,自引:0,他引:1  
简要回顾了基于磁性材料热疗的发展过程,介绍了恶性肿瘤局部热疗用纳米磁性材料目前的主要研究发展现状,并探讨了未来发展的方向,以及可能需要解决的一些问题。  相似文献   

8.
简要介绍了铁氧体磁性材料应用现状及其进展,并重点介绍了铁氧体磁性材料的自蔓延高温合成技术.自蔓延高温合成作为新兴的材料合成技术在铁氧体合成方面具有巨大潜力,文章结合SHS技术的特性进行了分析,指出了材料合成过程中的主要过程机理,并结合实验给出了SHS技术在铁氧体合成领域中应用与研究的技术关键与最新的发展动向.  相似文献   

9.
磁力显微镜观测是研究磁性材料强有力的手段之一,可以对磁性材料的磁畴结构进行直接的观测,利用磁力显微镜对磁记录媒体的研究更是目前研究人员关注的热点之一。本文介绍了目前非常先进的磁场内磁力显微镜观测技术对垂直磁记录媒体的研究。将磁力显微镜和可变化的磁场相结合,这样就可以观察到磁性材料在磁场内的磁结构的在线变化,从而得到磁性材料更多的信息。例如:利用该技术对垂直记录媒体进行研究可以对垂直记录媒体的磁化反转场分布进行测量,从而得到磁化反转场分布地图;利用磁化反转场地图技术可以对媒体的其它性能进行更深入的研究,包括磁化反转机制,激活体积的测量以及媒体噪音和媒体磁化反转场的关系等等。  相似文献   

10.
介绍了激光分子束外延(Laser Molecular Beam Epitaxy)的基本原理和技术特点,评述了激光分子束外延技术在超导材料和磁性材料方面所取得的主要成就,并给出了这种技术在材料科学领域的应用前景和发展潜力.  相似文献   

11.
From the standpoint of supramolecular chemistry major advances have been made concerning the functional properties of metal–ligand-based coordination complexes/extended solids/polymers. This paper reviews recent results from our laboratories on two contemporary areas of research: (i) spin-crossover FeIIN6 complexes which are representative examples of molecular bistability and (ii) synthesis of tailor-made transition-metal-based 1D coordination polymers and investigation of their magnetic exchange phenomena from the standpoint of molecule-based magnetic materials. Our primary focus is on the magnetic properties which seem to hold promise for future applications. It has been shown that covalent bond-driven discrete complexes/coordination polymers are further stabilized by association due to multiple weak, noncovalent interactions. In the design of FeIIN6 complexes our laboratories have so far relied on synthesis of discrete molecules. However, they are connected by noncovalent interactions, imparting cooperativity.  相似文献   

12.
Mixed-valence polycyanides (Prussian Blue analogues) possess a rich palette of properties spanning from room-temperature ferromagnetism to zero thermal expansion, which can be tuned by chemical modifications or the application of external stimuli (temperature, pressure, light irradiation). While molecule-based materials can combine physical and chemical properties associated with molecular-scale building blocks, their successful integration into real devices depends primarily on higher-order properties such as crystal size, shape, morphology, and organization. Herein a study of a new reduced-dimensionality system based on Prussian Blue analogues (PBAs) is presented. The system is built up by means of a modified Langmuir-Blodgett technique, where the PBA is synthesized from precursors in a self-limited reaction on a clay mineral surface. The focus of this work is understanding the magnetic properties of the PBAs in different periodic, low-dimensional arrangements, and the influence of the "on surface" synthesis on the final properties and dimensionality of the system.  相似文献   

13.
Enabling the use of rationally designed thin films in technological devices is a recognized goal in materials science. However, constructing such thin films using highly ordered supramolecular architectures with well-controlled size and growth direction has remained an elusive target. Here, we introduce a layer-by- layer protocol to grow hybrid thin films of molecule-based magnetic conductors comprising arachidic acid and donor bis(ethylenedioxy)tetrathiafulvalene (BEDO-TTF) as the organic component and Cu/Gd complexes as the inorganic component. The construction of layered hybrid thin films was achieved at ambient conditions by employing the Langmuir-Blodgett method, which provides good control over film thickness and packing of molecules in the monolayer. As demonstrated by X-ray diffraction, these films are crystalline with distinct organic and inorganic sublattices, where the BEDO-TTF molecular layer is interfaced with the inorganic layer. Due to the flexibility of the Langmuir-Blodgett deposition technique, this result indicates a route toward the preparation of well-ordered films with various functionalities, determined by the choice of the inorganic compound that is combined with the π-unit of BEDO-TFF. Moreover, the ability to deposit films on a variety of substrates establishes the potential for lower-cost device fabrication on inexpensive substrates.  相似文献   

14.
The conventional magnetic materials used in current technology, such as, Fe, Fe2O3, Cr2O3, SmCo5, Nd2Fe14B etc are all atom-based, and their preparation/processing require high temperature routes. Employing self-assembly methods, it is possible to engineer a bulk molecular material with long-range magnetic order, mainly because one can play with the weak intermolecular interactions. Since the first successful synthesis of molecular magnets in 1986, a large variety of them have been synthesized, which can be categorized on the basis of the chemical nature of the magnetic units involved: organic-, metal-based systems, heterobimetallic assemblies, or mixed organic-inorganic systems. The design of molecule-based magnets has also been extended to the design of poly-functional molecular magnets, such as those exhibiting second-order optical nonlinearity, liquid crystallinity, or chirality simultaneously with long-range magnetic order. Solubility, low density and biocompatibility are attractive features of molecular magnets. Being weakly coloured, unlike their opaque classical magnet ‘cousins’ listed above, possibilities of photomagnetic switching exist. Persistent efforts also continue to design the ever-elusive polymer magnets towards applications in industry. While providing a brief overview of the field of molecular magnetism, this article highlights some recent developments in it, with emphasis on a few studies from the author’s own lab.  相似文献   

15.
《Materials Today》2002,5(2):20-27
Molecular electronics and optoelectronics depend for their existence on the molecular organization of space. The fundamental mechanisms underlying the rich phenomena that have been discovered in these areas arise from mixing of electronic energies in the molecule with external, macroscopic structures. Mechanisms of charge injection and transport, and their manifestations in the physical properties of molecular electronic junctions, are discussed. Major questions that remain unresolved are placed in the contexts of fundamental understanding and device considerations.In the natural world, molecules are used for many purposes. Using molecule-based materials for electronics, sensing, and optoelectronics is a new endeavor, called molecular electronics, and the subject both of riveting new research and substantial popular press interest.  相似文献   

16.
Abstract

In the development of innovative molecule-based materials, the identification of the structural features in supramolecular solids and the understanding of the correlation between structure and function are important factors. The author investigated the development of supramolecular solid electrolytes by constructing ion conduction paths using a supramolecular hierarchical structure in molecular crystals because the ion conduction path is an attractive key structure due to its ability to generate solid-state ion diffusivity. The obtained molecular crystals exhibited selective lithium ion diffusion via conduction paths consisting of lithium bis(trifluoromethanesulfonyl)amide (LiTFSA) and small molecules such as ether or amine compounds. In the present review, the correlation between the crystal structure and ion conductivity of the obtained molecular crystals is addressed based on the systematic structural control of the ionic conduction paths through the modification of the component molecules. The relationship between the crystal structure and ion conductivity of the molecular crystals provides a guideline for the development of solid electrolytes based on supramolecular solids exhibiting rapid and selective lithium ion conduction.  相似文献   

17.
随着电力电子行业的飞速发展,新型电磁材料的投入使用,对电子元器件的高频磁性能提出了新的要求。磁芯作为电子元器件的核心部件,其发展程度直接决定电子元器件的性能,这就要求具有优异高频软磁性能的材料发展。本文综述了四种软磁材料的发展历程,对每种软磁材料的优缺点进行了归纳总结,同时指出了未来的发展方向,并重点对近年来研究热门的软磁复合材料进行了梳理。粒径大小可控、包覆层对核层的包覆均匀程度以及从实验室走向产业化的大批量制备方法是未来高频软磁复合材料的发展趋势。  相似文献   

18.
Static magnetic field processing of non-ferromagnetic materials has been of broad interest and been applied in such fields as drug delivery, colloid chemistry and engineering of materials containing particles. A ‘strong’ magnetic field refers to a ‘strong’ response from the manipulated material and can vary in definitions. The response is corresponding to a local interaction between the material and the local magnetic field, being influenced by the magnetic susceptibilities of the material and the surrounding/coated medium. By carefully designing the medium, a significantly ‘strong’ response from a weakly magnetic material can even be generated by a traditional magnet, i.e. magnetic flux density ∼0.01 T. Therefore, the ability to manipulate materials by using a magnetic field depends critically on the understanding of the principles of the magnetic properties of materials and their magnetic responses. This paper provides a critical discussion on the principles including magnetic field effect thermodynamics, magnetic energy, magnetic anisotropy and different magnetic forces during ’strong’ magnetic field processing of weakly magnetic materials (focusing on metallic materials). A series of case studies and the related magnetic field effect are subsequently integrated and discussed. Overall this review aims to provide a better understanding and efficient overview on the phenomenon principles in the field of magnetic field processing.  相似文献   

19.
综述了1995~1996年间几种磁性功能材料的新进展。这些材料包括高磁矩Fe-N化合物,高最大磁能积NdFeB永磁材料,庞磁电阻材料,Mn-Zn铁氧体大功率材料,新的Invar磁性材料和铁电反铁磁材料  相似文献   

20.
Recent advances on ab-initio computation of physical properties of magnetic materials are reviewed. The emphasis is put forward regarding the new development of the electronic structure methods, namely the calculation of magnetic anisotropy energy, X-ray magnetic dichroism, non-collinear magnetism, spin density wave, and spin fluctuations in materials. These theoretical advances have lead to new levels of understanding of magnetic materials. In particular, new results on magnetic anisotropy, surface and interface magnetism, and magnetic alloys will be briefly discussed.  相似文献   

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