Wooseung Kang
材料科学技术（英）
The effect of microforging on the processing of nanocrystalline FeSiB alloy flakes was studied in terms of microstructure and magnetic properties. The flakes microforged from amorphous precursor showed submicron thicknesses with the crystal size of about 15 nm. The crystallite size during microforging was primarily determined by plastic deformation rather than fracturing and agglomeration. Unlike the general trend of coercivity reduction with annealing, the coercivity of the nanocrystalline flakes was slightly increased with increasing annealing temperature, which can be explained with the diffusion anisotropy of the magnetic moments resulting from the formation of Fe-atoms pairs. The magnetic remanence (Mr) of the planar nanocrystalline flakes was
measured to be about 26% of the saturation magnetization (Ms), a significant increase from 2% of the initial amorphous precursor.
关键词:
Microforging
M.H.Khedr
,
A.A.Farghali
材料科学技术（英）
Copper ferrite, CuFe2O4, one of the important ferrites due to its interesting electrical, magnetic and structural properties, is obtained by a novel self flash combustion of a homogeneous mixture of one mole copper acetate monohydrate, Cu(CH3COO)2•H2O, and two moles of iron (III) acetate basic, Fe(CHCOO)2•OH. Nanocrystalite (89 nm) copper ferrite (less than 100%) is obtained at lower temperatures, whereas 100% copper ferrite is obtained after calcination at 1000℃. Thermal analysis (TG and DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), photo microscopy, magnetic and porosity measurements have been carried out for the specimens obtained after calcinations at 700, 800, 900 and 1000℃ to characterize the conversion efficiency of the powder precursors to copper ferrite. It was found that increasing temperature leads to great improvement in the magnetic properties. By increasing calcination temperature from 700～1000℃ saturation magnetic flux density (Bs) increased from 17.8 to 40.8 emu/g, while remnant magnetic flux density (Br) increased from 10.1 to 17.11 emu/g.
关键词:
Copper ferrite
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null
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null
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null
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null
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null
黄凤群
,
王治
,
成宁宁
材料开发与应用
doi:10.3969/j.issn.1003-1545.2012.03.010
采用溶胶凝胶自燃烧法制备了Mn0.4Zn0.6-xCoxFe2O4铁氧体,研究了钴掺杂对其结构和磁性质的影响.将自燃烧法制备的粉末进行1,150℃烧结.利用X射线衍射仪对制备的粉末测试发现,Mn0.4Zn0.6-xCoxFe2O4系列铁氧体都具有尖晶石结构.利用VSM对铁氧体进行磁性测试,发现饱和磁化强度与晶格常数的变化规律一致,在钴含量为0.2时,都取得最大值.通过μi-T曲线发现,初始磁导率随着钴含量的增加而降低,居里温度是一个常数.而且,钴含量可以调节磁导率的温度稳定性,在钴含量为0.3时,磁导率具有优良的温度稳定性.基于铁氧体中离子分布的原理,阐明了钴掺杂对铁氧体磁导率温度稳定性的作用机理.
关键词:
锰锌铁氧体
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溶胶凝胶自燃烧法
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钴掺杂
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磁性能
Dan LI
,
Yousong GU
,
Zuoren NIE
,
Bo WANG
,
Hui YAN
材料科学技术（英）
Pseudo-potential and plane wave basis-set under the framework of density functional theory have been employed to study the electronic and magnetic properties of Fe16N2, and to have an insight look on the subject of giant magnetic moments reported in Fe16N2. After geometrical optimization, band structures and densities of states have been evaluated together with the atom resolved band populations and magnetic moments. In this paper, we report a theoretical effort to look into the various aspects of the magnetic properties of Fe16N2, including volume effect and distortion effect.
关键词:
Ab initio calculations
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磁学性能
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Fe16N2系统
Yongli WU
,
O.Tegus
,
Weiguang ZHANG
,
S.Yiriyoltu
,
B. Mend Songlin
金属学报(英文版)
doi:10.1016/S1006-7191(08)60114-3
The magnetic properties and magnetocaloric effect in Fe4MnSi3Bx compounds with x=0, 0.05, 0.10, 0.15, 0.20, 0.25 have been investigated. X-ray diffraction study shows that all these compounds investigated crystallize in the Mn5Si3-type structure with space group P63/mcm. Boron insertion in the host ternary silicide Fe4MnSi3 does not change the crystal symmetry, only leads to an increase of the lattice parameters, indicating the B atoms entered the interstitial sites. With increasing B content, the Curie temperature shifts to higher temperatures. The maximal magnetic-entropy changes of the Fe4MnSi3Bx compounds with x=0, 0.10 and 0.20 are about 1.8 J/(kg·K), 1.8~J/(kg·K) and 1.6~J/(kg·K), respectively, for a field change from 0 to 1.5 T.
关键词:
Transition metal interstitial compounds
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null
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