Surface and bulk magnetic properties of amorphous and nanocrystalline Ni-substituted FINEMET samples
TL;DR: In this paper, the effect of partial substitution of Fe by Ni on the bulk and surface magnetic properties in as-quenched and nanocrystalline Fe 735− x Ni x Cu 1 Nb 3 Si 135 (x ǫ = 0, 8, 10 and 20) alloys has been investigated.
Abstract: The effect of partial substitution of Fe by Ni on the bulk and surface magnetic properties in as-quenched and nanocrystalline Fe 735− x Ni x Cu 1 Nb 3 Si 135 ( x = 0, 8, 10 and 20) alloys has been investigated A study of the variation of the surface magnetic properties with oxidation in these alloys is also presented The surface hysteresis loops were obtained by the transverse magneto-optical Kerr effect The experimental results show that the as-quenched and annealed samples with lower surface coercive field values are those with lower Fe/Si ratio in the sample surfaces No significant changes between the values of surface H c for the oxidized and non-oxidized annealed samples with the same Ni content have been observed
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TL;DR: In this article, the authors reviewed the different researches performed on Finemet up to now and explained the criteria that should be satisfied in order to have the high glass forming ability in an alloy and also the techniques applied for production of Finemet ribbons, powders and bulk samples.
83 citations
TL;DR: In this paper, the structure and magnetic properties of melt-spun Nix(Fe0.5Co 0.5)73.5B9Nb3Cu alloys were investigated at different temperatures.
Abstract: Structure and magnetic properties of melt-spun Nix(Fe0.5Co0.5)73.5−xSi13.5B9Nb3Cu alloys (x = 5,10,15,20,25,30) annealed at different temperatures were investigated. Microstructure has been analyzed from XRD patterns. Magnetic properties were mainly studied by the evolution of initial permeability from room temperature to 740 °C. All the 500 °C–annealed samples gave rise to an ultrafine structure composed of a residual amorphous matrix andα-FeCoNi(Si) crystals (tens of nanometers in size). It was found that Ni content had a significant impact on the Curie temperature of amorphous phaseTcam and initial permeabilityμi. There was a general reduced tendency ofTcam with Ni content increasing. For higher Ni content alloys (x≥25) annealed at 500 °C, theμi can be enhanced to the order of 104, which is much higher than that of Ni-free FeCo-based Finemet-type alloys. The reason for the enhancement inμi was systematically analyzed in terms of the effective anisotropy model.
15 citations
TL;DR: In this paper, the structure and magnetic properties of as-quenched and annealed Ni5(Fe0.5Co 0.5Si13.5)68.5Nb3B9Cu samples were investigated.
11 citations
TL;DR: In this article, Ni-content dependence on magnetostriction, effective magnetic anisotropy and initial permeability for as-quenched amorphous Nix(Fe 0.5Co0.5)73.5-xNb3Si13.5B9Cu1 (x=0 ~ 30) alloys annealed at 500°C was investigated.
Abstract: Ni-content dependence on magnetostriction, effective magnetic anisotropy and initial permeability for as-quenched amorphous Nix(Fe0.5Co0.5)73.5-xNb3Si13.5B9Cu1 (x=0 ~ 30) alloys annealed at 500°C was investigated. XRD showed that all the amorphous samples were partially nanocrystallized after annealing and a two-phase nanocrystalline structure with α-FeCoNi(Si) and residual amorphous phase was formed. Ni-content exerts a significant effect on magnetostriction and effective magnetic anisotropy. With the increasing of Ni-content, the magnetostriction and effective magnetic anisotropy gradually decreases which results in the remarkable enhancement of initial permeability from 3000(x=0) to 16000(x=30).
2 citations
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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.
Abstract: The magnetic properties of Fe‐Si‐B‐M (M: additives) 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. Excellent soft magnetic properties were obtained by adding the two elements Cu and Nb to Fe‐Si‐B alloys. It was found that these new alloys, called ‘‘FINEMET,’’ have an ultrafine grain structure composed of bcc Fe solid solution. They are suitable for many kinds of magnetic components such as saturable reactors, choke coils, and transformers, because they have superior soft magnetic properties and a high saturation flux density, and because different types of B‐H hysteresis loops are obtained by magnetic field annealing.
2,938 citations
TL;DR: In this paper, the demagnetizing factors of ellipsoids of three different axes are presented, along with supplementary formulas which cover a large number of special cases of ellipses.
Abstract: Charts and tables of the demagnetizing factors of prolate and oblate spheroids are readily available; however, demagnetizing factors of ellipsoids of three different axes are incompletely tabulated and laborious to calculate. This article presents charts and tables which make possible easy determination of the demagnetizing factor for any principal axis of an ellipsoid of any shape. Formulas for the demagnetizing factors of the general ellipsoid are included together with supplementary formulas which cover a large number of special cases.
2,032 citations
TL;DR: Nanocrystalline structures offer a new opportunity for tailoring soft magnetic materials The most prominent example are devitrified glassy FeCuNbSiB alloys which reveal a homogeneous ultrafine grain structure of bcc-FeSi with grain sizes of typically 10-15 nm and random texture.
Abstract: Nanocrystalline structures offer a new opportunity for tailoring soft magnetic materials The most prominent example are devitrified glassy FeCuNbSiB alloys which reveal a homogeneous ultrafine grain structure of bcc-FeSi with grain sizes of typically 10-15 nm and random texture Owing to the small grain size the local magneto-crystalline anisotropy is randomly averaged out by exchange interaction so that there is only a small anisotropy net-effect on the magnetization process Moreover the structural phases present lead to low or vanishing saturation magnetostriction which minimizes magneto-elastic anisotropies Both the suppressed magnetocrystalline anisotropy and the low magnetostriction provide the basis for the superior soft magnetic properties comparable to those of permalloys or near zero-magnetostrictive Co-base amorphous alloys but at a higher saturation induction Like in other soft magnetic material the hysteresis loop can be tailored by uniaxial anisotropies induced by magnetic field annealing
301 citations
TL;DR: In this article, the Johnson-Mehl-Avrami nucleation-and-growth (JMEG) and normal-grain-growth-like (NGG-like) modes were studied for a set of Fe-Cu-Nb-Si-B ribbons.
51 citations
TL;DR: In this paper, a systematic investigation about the influence of Ni content on structure and magnetic properties of melt-spun NixFe73.5−xSi13.5B9Nb3Cu1 (0.25) alloys has been performed.
Abstract: A systematic investigation about the influence of Ni content on structure and magnetic properties of melt-spun NixFe73.5−xSi13.5B9Nb3Cu1 (0⩽x⩽25) alloys has been performed. The study has been done in amorphous ribbons as well as after thermal treatments leading to structure relaxation, to partial devitrification into nanocrystalline state, and finally to full structural crystallization. Different characterization techniques have been employed. Structure has been investigated by x-ray diffraction, differential scanning calorimetry, and Mossbauer technique, while magnetic properties as coercivity, saturation magnetostriction constant, or Curie temperature have been studied by induction methods. Two main behaviors have been distinguished depending on the Ni content of the alloys: (i) Low Ni content (up to x=15), when Ni atoms diffuse towards Fe sites in the disordered bcc (Fe,Ni)3Si structure originating reduced structural distortion and small changes in magnetic properties as coercivity and (ii) High Ni con...
38 citations