共查询到18条相似文献,搜索用时 453 毫秒
1.
讨论了利用分子场近似结合中子衍射或X射线衍射的实验结果计算R2Fe17型稀土过渡族化合物中稀土磁矩与过渡族磁矩之间交换耦合常量的方法,并据此计算了R2Fe17-xAlx(R=Tb,Dy,Ho,Er,Gd,x=7或8)化合物中稀土磁矩与过渡族磁矩之间的交换耦合常量.计算结果与实验值符合较好. 相似文献
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熵调控材料因其独特的设计理念和优于传统合金的性能而受到广泛关注.本文将熵调控的设计理念引入金属间化合物中,设计并通过真空电弧熔炼的方法制备了一系列熵调控的Gd2Co17金属间化合物,期望通过熵调控的方法来稳定其结构,改善其磁性能.应用热力学理论预言熵调控的Gd2Co17系列金属间化合物具有稳定的单相,其单相性被X射线衍射实验所证实.通过组态熵调控原子尺寸因素,获得了菱方和六方两种晶体结构.熵调控改善了Gd2Co17系列金属间化合物的室温磁性能,过渡族金属位的熵调控使磁各向异性发生由基面到易轴的转变,稀土位的熵调控有助于提高其矫顽力,所有熵调控样品室温时的饱和磁矩均比二元Gd2Co17显著提升,可能是稀土或过渡族金属子晶格磁矩无序取向削弱了金属间化合物中稀土的4f电子与过渡族金属的3d电子磁矩之间的反平行交换作用所导致.磁价模型研究表明:熵调控设计导致Gd2Co17系列金... 相似文献
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The crystal structure and magnetic properties of R2Fe17-xCrx(R=Dy,Er,0≤x≤3) compounds have been investigated by me ans of X-ray diffraction and magnetization measurements. These compounds have hexagonal Th2Ni17-type structure. The unit-cell volumes decrease with the increase of Cr concentration x. The Curie temperature Tc of the Er2Fe17-xCrx compounds increases from 320 K for x=0 to 403 K for x=1.0 and then decreases with further increase of x. The Cur ie temperat ure Tc of Dy2Fe17-xCrx compounds increases from 364 K for x=0 to 435 K for x=1.0 and then decreases with further increase of x. The saturation magnetization of these compounds shows an approximately linear decrease with the increase of x. Spin reorientation transitions occur s in Er2Fe17-xCrx(x=2.0 and 3.0). 相似文献
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通过X射线衍射和磁性测量等手段研究了(Nd1-xGdx)3Fe27.31Ti1.69(0≤x≤0.6)化合物的结构和磁性.X射线衍射测量结果表明Gd替代后并未改变Nd3(Fe,Ti)29化合物的晶体结构,但引起了晶胞体积收缩.随着Gd含量的增加,化合物的居里温度TC和室温磁晶各向异性场Ba单调增加,而自旋重取向
关键词:
1-xGdx)3Fe27.31Ti1.69化合物')" href="#">(Nd1-xGdx)3Fe27.31Ti1.69化合物
磁晶各向异性
自旋重取向
磁相图 相似文献
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对多晶Y3Fe3Fe5-xMnxO12(x=0.05和0.09),得到300K下的中子衍射曲线。发现当x=0.05时,Mn3+离子占据16a和24d位置的几率分别为0.72和0.28;当x=0.09时,Mn3+离子全部占据16a位置;还得到两种组分16a和24d位置各自的磁矩值。在外磁场(800—10KOe)下测量Y3Fe5-xMnxO12(x=0—0.11)的磁化曲线,温度范围是1.5—300K。得到饱和磁矩值;并利用趋近饱和定律确定1.5K下的磁晶各向异性常数k1值,发现|k1|值随含锰量增加而减小。
关键词: 相似文献
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通过x射线衍射及磁测量手段研究了Y2(Fe1-y-x,Coy,C rx)17化合物的结 构及居里温度.研究结果表明Y2(Fe1-y-x,Coy,Crx)17化合物具有六 角相的Th2Ni17型结构.随着x的增加,Y2(Fe
关键词:
2(Fe1-y-x')" href="#">Y2(Fe1-y-x
y')" href="#">Coy
x)1 7化合物')" href="#">Crx)1 7化合物
x射线衍射
居里温度 相似文献
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We examined the magnetic structures of R2Mn2Se2O (R=LaO, BaF) by evaluating the spin exchange interactions on the basis of density functional theory (DFT) calculations, and compared how they differ from that of the Fe analog (BaF)2Fe2Se2O. In R2Mn2Se2O (R=LaO, BaF), the two-dimensional antiferromagnetic square lattice defined by J1 is spin-frustrated, and the exchange J1 is stronger for (LaO)2Mn2Se2O than for (BaF)2Mn2Se2O by a factor of 1.5 explaining why the magnetic susceptibility maximum occurs at a higher temperature for (LaO)2Mn2Se2O than for (BaF)2Mn2Se2O (360 vs. 210 K). We identified two probable reasons why the specific heat anomaly at the long-range antiferromagnetic ordering temperature TN is significantly weaker for R2Mn2Se2O than for (BaF)2Fe2Se2O. 相似文献
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In this paper the values of the crystalline-electric-field
parameters Anm for R2Fe17 and
R2Fe17H3 (R=Tb,Ho,Er) are evaluated by fitting
calculations to the magnetization curves measured on the single
crystal at several temperatures. The fitted Anm for
R2Fe17 are strikingly different from those for the
corresponding R2Fe17H3. The energy gaps between the
lowest four energy levels for Ho ions in Ho2Fe172 can be
reproduced by using the fitted Anm and exchange field
2μBHex, which estimated from the fit of the
temperature dependence of the spontaneous magnetization combined
with inelastic neutron scattering experiment. 相似文献
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The effect of high pressure on the crystal structure of the intermetallic compounds R2Fe17 − x
Six (R = Lu or Y; x = 0 or 1.7) was studied using neutron diffraction. A correlation between changes in structural parameters and magnetic properties
under the action of high pressure, as well as under chemical substitution of Si for Fe atoms, was analyzed in terms of localized
moment and spin fluctuation models. The spin fluctuation model was found to describe more adequately the experimentally observed
increase in the Curie temperature upon chemical substitution and the decrease in this temperature under the action of high
pressure. Possible reasons for the suppression of a collinear ferromagnetic state and the occurrence of a noncollinear antiferromagnetic
state in R2Fe17−x
Six under pressure are discussed based on estimated differences between the total energy minima of these states.
Original Russian Text ? D.P. Kozlenko, V.I. Voronin, V.P. Glazkov, B.N. Savenko, 2007, published in Pis’ma v Zhurnal éksperimental’noĭ
i Teoreticheskoĭ Fiziki, 2007, Vol. 86, No. 9, pp. 675–680. 相似文献
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Yifei Chen Qinggong SongHuiyu Yan Tong WeiXiong Yang 《Physica B: Condensed Matter》2012,407(3):519-522
Using first-principles calculations based on density functional theory, we investigated systematically the electronic structures and magnetic properties of Fe16N2 system and their unit cell volume dependence. It has been found that total magnetic moment increases as increasing unit cell volume of Fe16N2. In addition, it also has been found that the d electron number on Fe I, Fe II and Fe III atoms decreases as increasing unit cell volume and the local magnetic moment on Fe atoms increases with the decrease of d electron number. The present study provides a clear insight into the numerous conflicting experimental results on the magnetic properties of Fe16N2 system. 相似文献
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The effect of high pressure on the crystal structure of the intermetallic compounds R2Fe17 − x
Six (R = Lu or Y; x = 0 or 1.7) was studied using neutron diffraction. A correlation between changes in structural parameters and magnetic properties
under the action of high pressure, as well as under chemical substitution of Si for Fe atoms, was analyzed in terms of localized
moment and spin fluctuation models. The spin fluctuation model was found to describe more adequately the experimentally observed
increase in the Curie temperature upon chemical substitution and the decrease in this temperature under the action of high
pressure. Possible reasons for the suppression of a collinear ferromagnetic state and the occurrence of a noncollinear antiferromagnetic
state in R2Fe17−x
Six under pressure are discussed based on estimated differences between the total energy minima of these states. 相似文献