The effect of coherent uniaxial anisotropies on the grain-size dependence of coercivity in nanocrystalline soft magnetic alloys

Suzuki, Kiyonori; Herzer, G.; Cadogan, J. M.

doi:10.1016/s0304-8853(97)00987-6

Cited by 132 publications

(55 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For similar crystalline volume fractions the coercivity ratio between both alloys is H c (Cu free)/H c (Cu) < 5. This value cannot be apparently justified if we assume a potential dependence of coercivity with the grain size (a D 6 law [16] would give ratios of ∼4096 and a D 3 law [26] ratios of ∼64). Hernando et al [17] described the behaviour of magnetic anisotropy (k ef f ) as a function of the crystalline fraction (x) as where 0 < γ < 1 is the ability of the matrix to transmit the exchange coupling between the nanocrystals, dependent on x, λ S is the saturation magnetostriction constant, σ is the internal stress and k 0 is the average magnetocrystalline anisotropy, which is related to the grain diameter (D) by…”

Section: Cu Effect On the Magnetic Propertiesmentioning

confidence: 98%

The influence of Cu addition on the crystallization and magnetic properties of FeCoNbB alloys

Blázquez

Franco

Conde³

2002

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

The influence of Cu addition on the crystallization process, the nanocrystalline microstructure and the magnetic properties has been studied in the Fe 78−x Co x Nb 6 B 16−y Cu y (x = 18, 39, 60; y = 0, 1) alloy series. Cu addition clearly refines the nanocrystalline microstructure for the alloys with the lowest Co content, but the effect is reduced as the Co content increases. Refinement of the microstructure stabilizes the nanocrystalline microstructure by shifting the second crystallization process to higher temperatures. Cu addition mainly affects the magnetic properties for the lowest Co containing alloys. A fitting procedure of coercivity versus crystalline volume fraction is performed for these alloys in the frame of the random anisotropy model extended to twophase systems and assuming constant magnetoelastic anisotropy.

show abstract

Section: Cu Effect On the Magnetic Propertiesmentioning

confidence: 98%

The influence of Cu addition on the crystallization and magnetic properties of FeCoNbB alloys

Blázquez

Franco

Conde³

2002

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

show abstract

“…Deviation from the Herzer's D 6 law is also reported for the alloys such as Fe-Zr-B-(Cu) and Fe-P-C-Ge-Si-Cu. 24 The deviation is ascribed to the effect of induced anisotropies such as shape, magnetoelastic, and magnetic field induced anisotropies. In the simplest case of the presence of uniaxial anisotropy (K u ), the variation in average anisotropy follows D 3 law.…”

Section: -9mentioning

confidence: 99%

“…It is reported that the nanocrystalline alloys following D 3 law show significantly lower M r /M s (∼0.45) ratio than the D 6 law (∼0.95). 24 Separate investigations are required to understand the trend in the variation of anisotropy with D in the case of Fe-Si-B-P-Cu system. At present, we believe, the major difference in magnetic properties of sintered cores and the ribbons can originate from the shape, and orientation of powder particles in the sintered cores.…”

Section: -9mentioning

confidence: 99%

Sintered powder cores of high B s and low coreloss Fe84.3Si4B8P3Cu0.7 nano-crystalline alloy

2013

View full text Add to dashboard Cite

Nano-crystalline Fe-rich Fe84.3Si4B8P3Cu0.7 alloy ribbon with saturation magnetic flux density (Bs) close to Si-steel exhibits much lower core loss (Wt) than Si-Steels. Low glass forming ability of this alloy limits fabrication of magnetic cores only to stack/wound types. Here, we report on fabrication, structural, thermal and magnetic properties of bulk Fe84.3Si4B8P3Cu0.7 cores. Partially crystallized ribbons (obtained after salt-bath annealing treatment) were crushed into powdered form (by ball milling), and were compacted to high-density (∼88%) bulk cores by spark plasma sintering (SPS). Nano-crystalline structure (consisting of α-Fe grain in remaining amorphous matrix) similar to wound ribbon cores is preserved in the compacted cores. At 50 Hz, cores sintered at Ts = 680 K show Wt < 10 W/kg (f = 50 Hz, Bm ∼1 T). Coating/mixing of powders with an insulating agent like SiO2 is shown to be effective in further reduction of Wt at f > 1 kHz. A trade-off between porosity and electrical resistivity is necessary to get low Wt at higher f. In the f range of ∼1 to 100 kHz, we have shown that the cores mixed with SiO2 exhibit much lower Wt than Fe-powder cores, non-oriented Si-steel sheets and commercially available sintered cores. We believe our core material is very promising to make power electronics/electrical devices much more energy-efficient

show abstract

“…Therefore it is critical to achieve excellent soft magnetic properties by enhancing a-Fe amorphous dual phase structure formed in the primary crystallization and strictly prohibiting the precipitation of Fe-B(Zr) phase. Furthermore Suzuki et al [11] found that the coercivity (H c ) sharply increased with the growth of a-Fe grain and built up a dependence of the cubic grain size (d 3 ) on H c . As such, precise control of the a-Fe phase precipitation during the primary crystallization is important to optimize the soft magnetic properties in the Fe-based alloys.…”

Section: Introductionmentioning

confidence: 99%

Phase precipitation and isothermal crystallization kinetics of FeZrB amorphous alloy

et al. 2013

View full text Add to dashboard Cite

The crystallization process of Fe 78 Zr 7 B 15 (at%) amorphous ribbon was investigated by X-ray diffraction (XRD), differential scanning calorimetry and scanning electron microscopy (SEM). The fully amorphous structure of as-quenched (Aq) ribbons was confirmed by XRD pattern. The saturation magnetization (M s ) and Curie temperature of the Aq ribbon were measured as 124.3 (AÁm 2 )/kg and 305°C with vibrating sample magnetometer (VSM), respectively. When the ribbons was annealed at 550°C near the first onset temperature (T x1 = 564.9°C), the M s was increased by 17 %, which was caused by the formation of a dual phase structure. The isothermal crystallization kinetics and crystallization mechanism of primary a-Fe phase in the dual phase structure were studied by Arrhenius and Johnson-Mehl-Avrami-Kolmogorov equations respectively. The results showed that the crystallization of a-Fe phase was a diffusion-controlled surface nucleation growth process, and the nucleation rate decreased with longer crystallization time.

show abstract

The effect of coherent uniaxial anisotropies on the grain-size dependence of coercivity in nanocrystalline soft magnetic alloys

Cited by 132 publications

References 9 publications

The influence of Cu addition on the crystallization and magnetic properties of FeCoNbB alloys

The influence of Cu addition on the crystallization and magnetic properties of FeCoNbB alloys

Sintered powder cores of high B s and low coreloss Fe84.3Si4B8P3Cu0.7 nano-crystalline alloy

Phase precipitation and isothermal crystallization kinetics of FeZrB amorphous alloy

Contact Info

Product

Resources

About