Index of content:
Volume 85, Issue 8, 15 April 1999
- AMORPHOUS/NANOCRYSTALLINE ALLOYS
85(1999); http://dx.doi.org/10.1063/1.369098View Description Hide Description
A two-phase system of Fe-based nanocrystalline alloys is here investigated. The nanocrystalline alloys, which consist of two magnetic phases: α-FeSi grains and an amorphous matrix, were prepared by annealing the amorphous ribbons. Mössbauer spectroscopy and magnetic measurements at elevated temperatures were carried out. The results show that the exchange coupling interaction exists between grains through the amorphous matrix, and obviously affect the soft magnetic properties of the nanocrystalline alloys. A phenomenological coupling model is applied to estimate the coupling intensity for samples annealed at different temperatures and the data can reasonably explain why the nanocrystalline alloys annealed at 540 °C hold the best soft magnetic properties.
Effect of Ti, V, Cr, and Mn additions on the magnetic properties of a nanocrystalline soft magnetic Fe–Zr–B alloy with high magnetic flux density85(1999); http://dx.doi.org/10.1063/1.369099View Description Hide Description
The effect of the addition of Ti, V, Cr, and Mn on the magnetic properties of a nanocrystalline soft magnetic Fe–Zr–B alloy has been investigated. The addition of the elements increases both the crystallization temperature and the grain size of α-Fe. After crystallization, these elements are observed in both the α-Fe grains and the residual amorphous matrix. It has been found that V is a useful element to control magnetostriction by keeping the saturationmagnetic flux density high. The simultaneous addition of V and Mn increases The alloys with high above 1.75 T, show good soft magnetic properties as well; the alloy exhibits high of 1.75 T and high permeability of 31 000, and the alloy exhibits high of 1.78 T and high of 23 000. These high values are almost the same as that of a Fe-6.5 wt % Si alloy. The alloys also exhibit low core loss. Therefore, nanocrystalline Fe–V–(Mn)–Zr–B alloys are expected to be applied to power electronic devices such as power transformers.
85(1999); http://dx.doi.org/10.1063/1.369100View Description Hide Description
The temperature dependence of the magnetization for amorphous alloy has been measured. has been fit using a Handrich–Kobe model with a modified Brillouin function with an additional exchange fluctuation term. Here for the first time, an asymmetrical distribution of the exchange interactions is proposed based on empirical knowledge of the Bethe–Slater curve. A two-parameter exchange fluctuation is shown to give significantly better fits to for these amorphous alloys.
85(1999); http://dx.doi.org/10.1063/1.369101View Description Hide Description
The energetic model of ferromagnetic hysteresis calculates the magnetic state of materials by minimizing the total energy function for statistical domain behavior. The physical constants of this model are derived from anisotropy energy constants, initial susceptibility, coercivity, and saturation magnetization. The approach shows a good agreement to the magnetization curves of FeCoB strips, also in dependence of applied stress.
85(1999); http://dx.doi.org/10.1063/1.369102View Description Hide Description
Amorphousalloys with a wide supercooled liquid region before crystallization were formed in the (M=Nb, Ta)alloys by melt spinning. The which is a critical factor of glass-forming ability, increases to large values exceeding 90 from 82 K by the addition of 2 at. % M, and the largest value is larger by about 10 K than the largest value for recently reported (Fe,Co,Ni)–Zr–M–B alloys. By the addition of the M metals, magnetic properties also changed. Good soft magnetic properties were obtained for the alloysannealed for 300 s at 800 K. The saturation magnetization coercive force and effective permeability at 1 kHz are, respectively, 0.71 T, 1.0 A/m, and 16 700 for the M=Nb alloy and 0.76 T, 1.0 A/m, and 15 600 for the M=Ta alloy. The finding of the Fe-based amorphousalloys exhibiting simultaneously the wide supercooled liquid region before crystallization and the good soft magnetic properties seem to enable the future development of a new ferromagnetic bulk amorphousalloy.