1,721,045 research outputs found
Effect of nitrogen on the size and distribution of and precipitates in 3% silicon steel
No full textX115sciescopu
Saturation magnetizations and Curie temperatures of Co-Zn Y-type ferrites
No full textThis work studies the sigma(s) and T-C of Co-Zn mixed Y-type ferrite (BaCo1-xZnxFe6O11, x = 0-1) powders, prepared by the co-precipitation method. The sigma(s, 0 kappa) and T-C change linearly with zinc content. CoY shows the highest T-C (595 K) and the lowest sigma(s, 0 kappa) (32.1 emu/g), while ZnY has the lowest T-C (373 K) and the highest sigma(s, 0 kappa) (73.6 emu/g). At room temperature, however, the maximum sigma(s) appears at around x = 0.75 (34.9 emu/g). The presence of zinc weakens the superexchange interaction, without changing the spin directions of other cations, over the whole composition range. It simply increases the net magnetic moment.X1133sciescopu
Analysis of coating weight and iron content for iron-zinc alloy coatings by using X-ray fluorescence with multiple regression
No full textZinc-iron alloy coatings are produced by annealing of zinc-coated steels, in which the iron and the zinc are interdiffued to form iron-zinc alloy. The analysis of the coating weight and the iron content within the coating is very important since they are closely related to the corrosion properties. However, it is difficult to measure these alloy coatings by using the conventional X-ray fluorescence (XRF) method because iron is contained both in the coatings and the substrate. Furthermore, there is some concern that the non-uniform concentration of iron within the coatings may result in significant errors in the XRF analysis. The difference in probing depth for Zn Kalpha and Zn La lines can be used to separate the iron contained in the coating from that in the steel. The critical coating weights for the Zn Kalpha and the Zn Lalpha lines, were determined by fitting the line intensities of zinc electroplated coatings, and the coating weights of commonly produced zinc-iron alloy coatings were found to be higher than the critical coating weight, for the Zn Lalpha line and lower than that for, the Zn Kalpha line. A multiple regression method was successfully applied with the Zn Kalpha and the Zn La line intensities for the determination of the coating weight. The iron contents in the-coatings were determined by using the Zn Lalpha line only. With the proposed method, a coating weight accuracy to 0.57 g/m(2) and an iron content to 0.57 % was achieved for a number of commercially produced zinc-iron alloy coatings.X112sciescopuskc
Characterization of Heusler alloy thin film, Cu2MnAl and Co2MnSi, deposited by co-sputtering method
No full textThin films of Heusler alloy, Cu(2)MnA1 and Co2MnSi were fabricated successfully, by the co-sputtering method. Magnetic and structural properties are strongly dependent on substrate temperature. The films fabricated at room temperature show paramagnetic behaviour and amorphous or very fine crystalline feature in XRD and TEM analysis. On increasing substrate temperature, there appear polycrystalline features of L2, structure, accompanied by ferromagnetic properties. Also, the electrical resistivity implies that the electronic structures are heavily disturbed in the films fabricated at room temperature. These results suggest that structural ordering strongly affects the magnetic and electrical properties of Cu2MnA1 and Co2MnSi. The Curie temperature and saturation magnetization of Co2MnSi, Cu(2)MnA1 are 950 K (with extrapolation), 1100 emu/cc and 600 K, 440 emu/cc, respectively. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.X1117sciescopu
On factors inducing the (10(1)over-bar-0) texture of hexagonal-close-packed Co63Cr31Mn6 layers in magnetic recording media
No full textWe investigate factors affecting the movement of sputtered species and the (10 (1) over bar0) texture formation of hexagonal-close-packed Co63Cr31Mn6 (CoCrMn) layers in magnetic recording media. Deposition conditions and underlayers rendering high mobility of the sputtered species promote the (10 (1) over bar0) texture of the CoCrMn film. Elemental effects are studied by substituting manganese with a series of 3d transition elements (Ti, V, Cr, Fe, Ni, and Cu) in the CoCrMn films. The results suggest that the chemical characteristics of manganese, the preference of bonding with different elements (especially with cobalt), is important in the texture formation of CoCrMn films. (C) 2004 American Institute of Physics.open1111sciescopu
ION DISTRIBUTION AND SATURATION MAGNETIZATION OF ALUMINUM SUBSTITUTED LITHIUM FERRITES
No full textIon distribution is determined in a series of aluminum substituted lithium ferrites by carefully analyzing the powder X-ray diffraction patterns. A new finding is that Al+3's substitute the Fe+3's in tetrahedral sites as well as in octahedral sites of the spinel structure. The proper formula, then, is (Fe(+3)1-a Al(+3)a) [Li0.5+Fe1.5-(x-a+3)Al-x-a(+3)](4), where a is approximately 0.23x(2)+0.22x. The saturation magnetizations are calculated and compared with the measured values.X117sciescopu
Effects of P-O2 at Flux State on the Fluorine Dissolution from Synthetic Steelmaking Slag in Aqueous Solution
No full textThis paper studies effect of oxygen partial pressure at molten flux state on the fluorine dissolution from synthetic steelmaking slag solidified from the flux. The P-O2's were set as 6.6 x 10(-8), 8.1 x 10(-5), 2.9 x 10(-3), 1.5 x 10(-2), 1.1 x 10(-1), or 6.6 x 10(3) Pa, by changing the CO/CO2 ratio of environmental flowing gas. The Ca : Al : Fe atomic ratio of major cations of the slag (oxide) is 23 : 9 : 13, and minor constituents are Mg (similar to 3at%) and F (similar to 0.3at%). The phases and their distribution is characterized using SEM, EDS (point and mapping), Rietveld refinement of XRD. Increase of P-O2 reduces fluorine dissolution, and the amounts of dissolution are higher than 1 mg/L when processed at P-O2 10(-2) Pa. These results indicate that the low P-O2 processed slag has large fraction of low density Mayenite (Ca12Al14O33) with most of fluorine in its sparse crystal structure, and liberates large amount of fluorine. On the contrary, the high P-O2 processed slag is mainly composed of high density Brownmillerite (Ca2AlxFe2-xO5), and the fluorine exists as CaF2 particles not to liberate fluorine easily. It is concluded that the fluorine dissolution is strongly governed by the amount of phases, the density and empty space of each crystal structure to accommodate fluorine, and their distribution.X11sciescopu
ZnO thin films prepared by atomic layer deposition and rf sputtering as an active layer for thin film transistor
No full textRecently, the application of ZnO thin films as an active channel layer of transparent thin film transistor (TFT) has become of great interest. In this study, we deposited ZnO thin films by atomic layer deposition (ALD) from diethyl Zn (DEZ) as a metal precursor and water as a reactant at growth temperatures between 100 and 250 degrees C. At typical growth conditions, pure ZnO thin films were obtained without any detectable carbon contamination. For comparison of key film properties including microstructure and chemical and electrical properties, ZnO films were also prepared by rf sputtering at room temperature. The microstructure analyses by X-ray diffraction have shown that both of the ALD and sputtered ZnO thin films have (002) preferred orientation. At low growth temperature T-s 10 Omega cm) with small mobility (15 cm(2)/V s). Meanwhile, sputtered ZnO films have much higher resistivity than ALD ZnO at most of the growth conditions studied. Based upon the experimental results, the electrical properties of ZnO thin films depending on the growth conditions for application as an active channel layer of TFT were discussed focusing on the comparisons between ALD and sputtering. (C) 2007 Elsevier B.V. All rights reserved.11115sciescopu
An effective medium model applied to the conductivity of La-Ca-Mn-O across the phase transition temperature
No full textColossal magnetoresistance is closely related to (bur is not) the abrupt change of electrical resistivity in the vicinity of Curie temperature, which is caused by the temperature-dependent paramagnetic-ferromagnetic phase transition and concurrent change of electrical conducting mechanism. A model equation based on the effective medium theory is presented to explain the abrupt change of resistivity in the vicinity of Curie temperature of La-Ca-Mn-O (LCMO). II is assumed that LCMO is in the form of mixture of ferromagnetic and paramagnetic phase in the magnetic transition region. The main ingredients of the equation are a simple effective medium theory and a Function For thr temperature-dependent fraction of ferromagnetic phase. This model fits very well to the measured resistance-temperature curves of La0.7Ca0.3MnO3. (C) 2000 Elsevier Science B.V. All rights reserved.X119sciescopu
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