Journal ArticleDOI
Grain size dependence of coercivity and permeability in nanocrystalline ferromagnets
Giselher Herzer
- Vol. 26, Iss: 5, pp 1397-1402
TLDR
In this article, a series of crystallized ribbons of composition Fe/sub 74.5-x/Cu/sub x/Nb/sub 3/Si/sub 13.5/B/sub 9/ (x=0, 1 at) have been annealed between about 500 degrees C and 900 degrees C.Abstract:
Amorphous ribbons of composition Fe/sub 74.5-x/Cu/sub x/Nb/sub 3/Si/sub 13.5/B/sub 9/ (x=0, 1 at.%) have been annealed between about 500 degrees C and 900 degrees C. This produced a series of crystallized samples with grain sizes between about 10 nm and 300 nm and with coercivities H/sub c/ and initial permeabilities mu /sub i/ varying over several orders of magnitude. The best soft magnetic properties (H/sub c/ approximately=0.01 A/cm and mu /sub i/ approximately=80*10/sup 3/) were observed for the smallest grain sized of about 10 nm. With increasing grain size D, coercivity steeply increases following a D/sup 6/-power law (up to D approximately=50 nm). H/sub c/ then runs through a maximum of H/sub c/ approximately=30 A/cm and decreases again for grain sizes above 150 nm according to the well-known 1/D law for polycrystalline magnets. The initial permeability was found to vary in a similar manner, essentially being inversely proportional to coercivity. The variation of the soft magnetic properties with the average grain size is discussed and compared with the predictions of the random anisotropy model and other theories for the magnetization reversal. >read more
Citations
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Journal ArticleDOI
Amorphous and nanocrystalline materials for applications as soft magnets
TL;DR: In this paper, the authors summarize the recent developments in the synthesis, structural characterization, properties, and applications of amorphous and nanocrystalline soft magnetic materials, including: kinetics and thermodynamics, structure, microstructure, and intrinsic and extrinsic magnetic properties.
Journal ArticleDOI
Size effects in materials due to microstructural and dimensional constraints: a comparative review
TL;DR: In this article, the effects of size on predominantly mechanical properties of materials are reviewed at a first-order level, and important aspects can be understood from the point of view of the interaction of a characteristic length (which may be as diverse as the dislocation radius of curvature at a given stress or the magnetic exchange length) with a size parameter (grain or particle size, or film thickness).
Journal ArticleDOI
Size dependence of nanostructures: Impact of bond order deficiency
Chang Q. Sun,Chang Q. Sun +1 more
TL;DR: The BOLS correlation mechanism has been initiated and intensively verified as discussed by the authors, which has enabled the tunability of a variety of properties of a nanosolid to be universally reconciled to the effect of bond order deficiency of atoms at sites surrounding defects or near the surface edges of the nano-material.
Journal ArticleDOI
Modern soft magnets: Amorphous and nanocrystalline materials
TL;DR: In this paper, a survey of amorphous and nanocrystalline alloys for soft magnetic applications is presented, starting from the technique of production and including the key factors that determine their properties.
Journal ArticleDOI
Nanocrystalline metals crystallized from amorphous solids: nanocrystallization, structure, and properties
TL;DR: A review of the state of the art in this field can be found in this article, where the current status of research and developments on the nanocrystallization, microstructure and properties of the materials are summarized.
References
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Journal ArticleDOI
New Fe-based soft magnetic alloys composed of ultrafine grain structure
TL;DR: In this paper, the magnetic properties of Fe•Si•B•M alloys prepared by annealing amorphous alloys made by the single roller method over their crystallization temperature have been investigated for development of new Fe•based soft magnetic alloys.
Journal ArticleDOI
Grain structure and magnetism of nanocrystalline ferromagnets
TL;DR: Amorphous ribbons of composition Fe/sub 73.5,Cu/sub 1/Nb/sub 3/Si/sub 13.5/B/sub 9/ have been annealed above their crystallization temperature, which produces a homogeneous, ultrafine grain structure of alpha FeSi with typical grain diameters of 10-20 nm.
Journal ArticleDOI
Random anisotropy in amorphous ferromagnets
R. Alben,J. J. Becker,M. C. Chi +2 more
TL;DR: In this article, the effect of strong random anisotropy in materials such as amorphous Tb•Fe and Dy•Fe at low temperature and also examine the role which weak random an isotropy might play in even ideally homogeneous soft materials.
Journal ArticleDOI
Development of Elongated Particle Magnets
TL;DR: In this article, the present status of fine particle magnet materials is discussed from the viewpoint of our present understanding and lack of understanding of their behavior, and the present methods of preparation and the various theoretical descriptions of the properties of elongated particles are reviewed.