Papers by Keyword: Soft Magnetic Property

Abstract: Bulk Fe-50at%Ni alloy melts were undercooled using cyclic superheating and glass slag purification. As a result, a maximum undercooling up to 217 K could be achieved. As-solidified microstructures were observed by means of optical microscope. Phase identification of Fe-50at%Ni alloys was performed using the Shimadzu X-ray diffractometer (XRD) system. The chemical constitution revealed using a JEOL Model JSM-6700F scanning electron microscope equipped with energy dispersive X-ray spectroscopy (EDX). The magnetic properties of the alloys were measured by vibrating sample magnetometer (VSM) with a DC M-H analyzer. The results indicated that there were twice grain refinements occurred within an undercooling range of 55-217K, where the first could be ascribed to dendrite-remelting, and the second to recrystallization. The phase composition of undercooled Fe-50at%Ni alloys comprised two phases, i.e., solid solution phases with bcc and fcc structure. At various undercoolings, the saturation magnetization M_s and H_c related closely to the measured grain size D, and they were in proportion to D^-1 by the regression analysis.

Abstract: The initial permeability μ' (at 0.1 GHz) of Ba3Co2R0.1Fe23.9O41 (x=0.1, R= Gd, Dy, Ho, Yb) samples is higher than that of the Co2Z ferrite without substitution. In particular, μ' of Gd3+ substituted Z-type ferrite sample (x=0.1) is the highest of all samples. The substituted sample of Ba3Co2TixZnxFe24-2xO41 with x= 0.85 has a maximumμ' of 24, which is twice as large as that of the non-substituted sample with x=0. Ba3Co2-2x LixFe24+xO41(x=0-1.0) are also prepared. The sample with x=0 showsμ'of 8 at 50MHz. The maximumμ' is 24.5 at x=0.3. An apparent magnetic anisotropy constant K*, calculated by using HA* and MS, decreases. Therefore, the decrease of the magnetic anisotropy contributes to the increase of μ'.

Abstract: Bulk Fe-80at%Ni melts were undercooled by using cyclic superheating and glass slag purification technique, and the maximum undercooling 340 K could be achieved. The microstructures of Fe-80at%Ni alloys were observed by means of optical microscope (OM). The phase composition was identified by X-ray diffraction (XRD) analysis. The magnetic properties of Fe-80at%Ni alloys were measured by vibrating sample magnetometer (VSM) with a DC M-H analyzer. The results showed that there was only single γ-(Fe, Ni) phase existing in undercooled Fe-80at%Ni alloys. Two grain refinements and one grain coarsening were observed in the undercooling range from 28 K to 340 K. The first grain refinement could be ascribed to dendrite-remelting, and the second to recrystallization induced by the stress originating from rapid solidification. The grain coarsening could be considered as a result of solid-state grain coalescence. The measurement of soft magnetic properties showed that the grain size D decreases with an increase of undercooling, the maximum Ms is 109.98emu/g, corresponding to minimum grain size 42.9μm or undercooling 210 K, and the coercive force Hc is in proportion to the reciprocal of grain size D-1.

Abstract: In this work, (Fe,Co)–Zr–B–Cu films have been deposited on glass and Si substrates by DC magnetron sputtering method. X-ray diffraction analysis was used to identify the structure of the films. A transmission electron microscope (TEM) was employed to observe the microstructure for the films. Magnetic properties at room temperature were investigated by a Vibrating Sample Magnetometer (VSM). It was obtained that the as-deposited films on glass and Si substrates were in an amorphous state. In addition, it has been found that the coercivity is dependent on film thicknesses.