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1.
系统研究了室温下Tb0.3Dy0.7(Fe0.9T0.1)1.95(过渡金属元素T=Mn,Fe,Co,B,Al,Ga)合金中ⅢA族金属和过渡金属元素T替代Fe对结构、自旋重取向和穆斯堡尔谱的影响.结果发现,不同金属T替代Fe,Tb0.3Dy0.7(Fe0.9T0.1)1.95,合金具有相同的MgCu2型立方Laves相结构;Al,Ga替代使Tb0.3Dy0.7(Fe0.9T0.1)1.95合金的易磁化方向在{110}面逐渐偏离了立方晶体的主对称轴,即自旋重取向,B,Mn,Co替代未使易磁化轴发生明显转动;Al,Ga元素替代使超精细场Hhf略有下降,B,Mn替代对超精细场Hhf的影响不大,而Co元素替代使超精细场Hhf有较大增加;所有元素替代使同质异能移IS有所增加;B,Al,Ga和Mn替代使四极劈裂Qs增加,而Co替代使四极劈裂Qs下降.
关键词:
立方Laves相
自旋重取向
穆斯堡尔谱 相似文献
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X射线衍射实验表明YBa2(Cu0.95M0.05)3O7-δ(M=Ti,V,Cr,Mn,Fe,Co,Ni,Cu和Zn)均为单相结构。Fe,Co,Ni和Zn对Cu的替代使超导临界温度Tc显著下降,而同样含量的Ti,V,Cr,Mn对Cu的替代并未对超导性能产生显著影响。并利用中子衍射分析了Ti,Mn,Fe和Co对Cu原子的取代,发现代换原子对Cu的两个晶位各自存在不同的择优占据
关键词: 相似文献
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本文采用速凝甩带-氢破-气流磨-取向成型-烧结回火等工序,同时添加Dy和Co元素,制备了烧结Nd25.5Dy6.5Co13FebalM1.05B0.98磁体(Co13磁体),室温下磁能积(BH)max=30.88 MGOe,矫顽力Hcj=19.01 kOe.与Nd30Dy1.5Co0.5FebalM1.05B0.98(35SH)磁体相比, Co13磁体的室温磁性能略低,但温度稳定性显著提升,剩磁温度系数α从–0.136%/℃提升至–0.065%/℃(室温—180℃);居里温度TC从310℃升高至约454℃;最高使用温度TW从165℃提升到约200℃.力学性能测试和断口分析表明, Co13磁体中由于Co含量较高,主相晶粒发生解理断裂的比例提高... 相似文献
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通过X射线衍射分析和磁测量研究了Gd-Fe-Co-Cr四元系中对应于化学式Gd3(Fe,Co,Cr)29且Gd含量为一定值的截面内富Fe,Co区的相关系,重点探索了高Co含量3∶29型化合物合成的可能性,研究了3∶29型Gd3(Fe1-xCox)29-yCry化合物的结构与磁性.研究结果表明,获得3∶29型单相Gd3(Fe1-xCox)29-yCry化合物的范围为:y=5,0≤x≤0.7;y=5.5,0.7≤x≤0.8和y=6,0.8≤x≤0.9.基于对Gd3(Fe1-xCox)29-yCry化合物成相条件的研究,成功地合成了纯Co基Gd3Co29-yCry化合物,其固溶范围为6.5≤y≤7.3.3∶29型单相Gd3(Fe1-xCox)29-yCry化合物的晶体结构都属于单斜晶系,Nd3(Fe,Ti)29型结构,空间群为A2m.得到3∶29型单相Gd3(Fe1-xCox)29-yCry化合物的固溶极限即Co含量的极大值与稳定元素Cr含量有关.Co原子的含量越高,所需稳定元素Cr的含量越大.值得注意的是,用Co原子替代Fe原子会导致Gd3(Fe1-xCox)29-yCry化合物磁晶各向异性的显著改变.当x≥0.4时,化合物的磁晶各向异性从易面型转变为易轴型
关键词:
3(Fe1-xCox)29-yCry化合物')" href="#">Gd3(Fe1-xCox)29-yCry化合物
相关系和相结构
X射线衍射
磁晶各向异性 相似文献
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通过熔体快淬方法获得Pr(Fe1-xCox)2合金条带,经过X射线衍射、差示扫描量热计和磁性测量对其结构、磁性和热稳定性进行了研究.发现当Co的含量x大于0.2时才可能获得Pr(Fe,Co)2立方Laves相化合物.对Pr(Fe0.6Co0.4)2合金,在快淬速度为30m/s时,条带由Pr2(Fe,Co)17,Pr(Fe,Co)2和富稀土相组成;在速度为40m/s时,获得了几乎单相的Pr(Fe0.6Co0.4)2化合物,其居里温度为305℃;在速度为45m/s时,除了Pr(Fe0.6Co0.4)2化合物外,还存在少量的非晶相.Pr(Fe0.6Co0.4)2化合物在770℃以上发生分解.用40m/s快淬纳米晶粉胶粘磁体有大的磁致伸缩系数(λ∥-λ⊥=140×10-6)和高的硬磁性能(iHc=398kA/m).
关键词: 相似文献
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本文采用高温有机溶剂法制备了(Fe1-xCox)3BO5纳米棒, 通过控制反应物中乙酰丙酮钴的含量合成了不同Co含量的(Fe1-xCox)3BO5. 利用高分辨透射电子显微镜(HRTEM)、超导量子干涉磁强计(SQUID)对其形貌和磁性能进行了表征. 高分辨透射电子显微镜结果表明制备出的纳米(Fe1-xCox)3BO5为多晶棒状, 且具有多折孪晶结构; 磁性测量的结果表明,(Fe1-xCox)3BO5纳米棒在室温下表现出铁磁性, 随着Co含量的增加, 纳米棒的铁磁性逐渐增加, 该纳米棒有望用来研究生物大分子的机械性能. 相似文献
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PdAu25Fe21和PdAu24Fe21Al4合金(以下简称PdAuFe,PdAuFeAl)分别在临界温度500℃和550℃产生无序—有序转变。有序相是典型的Cu3Au型结构。有序化时合金由铁磁体转变为反铁磁体,电导率和磁化率大大减小,热电势改变符号。研究结果表明,合金反常的电磁特性起因于原子的有序排列和d带电子能态的变化。
关键词: 相似文献
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本文对Nd-Fe-Si三元系富铁区域相的结构和磁性进行了研究。结果表明,Nd-Fe-Si三元系富铁区域(Fe>40at%),除出现NdFe2Si2三元金属间化合物外(Si>20at%),同时只出现Nd2(Fe,Si)17赝二元金属间化合物,其中Si取代9d位的Fe原子,而不能形成类似于Nd2Fe14B的三元金属间化合物,Si取代Nd2Fe17中的9d位Fe原子后,使晶胞体积缩小;使饱和磁化强度减小;同时使Fe次晶格的铁磁相互作用增强,导致居里温度增高;还使得Fe次晶格的易面各向异性减弱,造成室温下各向异性场减小。
关键词: 相似文献
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A comparative study of the structure and crystallization of bulk metallic amorphous rod Pr60Ni30Al10 and melt-spun metallic amorphous ribbon Al87Ni10Pr3 总被引:1,自引:0,他引:1 下载免费PDF全文
Pr-based bulk metallic amorphous (BMA) rods (Pr60Ni30Al10) and Al-based amorphous ribbons (Al87Ni10Pr3) have been prepared by using copper mould casting and single roller melt-spun techniques, respectively. Thermal parameters deduced from differential scanning calorimeter (DSC) indicate that the glass-forming ability (GFA) of Pr60Ni30Al10 BMA rod is far higher than that of Al87Ni10Pr3 ribbon. A comparative study about the differences in structure between the two kinds of glass-forming alloys, superheated viscosity and crystallization are also made. Compared with the amorphous alloy Al87Ni10Pr3, the BMA alloy Pr60Ni30Al10 shows high thermal stability and large viscosity, small diffusivity at the same superheated temperatures. The results of x-Ray diffraction (XRD) and transmission electron microscope (TEM) show the pronounced difference in structure between the two amorphous alloys. Together with crystallization results, the main structure compositions of the amorphous samples are confirmed. It seems that the higher the GFA, the more topological type clusters in the Pr-Ni-Al amorphous alloys, the GFAs of the present glass-forming alloys are closely related to their structures. 相似文献
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From the Mössbauer investigation of amorphous Fe40Ni40B20 and Fe80B20 alloys it was found that the substitution of Fe by Ni only shifts but does not influence the shape of the iron hyperfine field distribution contrary to that of crystalline f.c.c. Ni-Fe alloys suggesting a rather localized type of behaviour. The distributions of the linear combinations of isomer shift and quadrupole splitting are affected by this substitution. 相似文献
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The magnetic behavior of amorphous Nd4(Fe0.75Cr0.25)77.5B18.5 alloys was investigated in the critical region. The Curie temperature TC and critical exponents β, γ and δ are found to be 141 K, 0.45±0.02, 1.64±0.08 and 4.66±0.10, respectively. The data are fitted to a magnetic equation of state characteristic of a second-order phase transition over a rather wide range of temperatures both above and below TC. It is noted that the values of the exponents are in disagreement with those derived for a three-dimensional Heisenberg ferromagnet and show an enhancement. This anomalous critical behavior may originate from magnetic inhomogeneity. 相似文献
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A. Grabias M. Kopcewicz J. Latuch M. P?ka?a 《Journal of magnetism and magnetic materials》2010,322(20):3137-3141
Structural and magnetic properties of two rapidly solidified and post-annealed Fe60Pt15B25 and Fe60Pt25B15 alloys are compared. The as-quenched Fe60Pt15B25 ribbon was fully amorphous whereas in the Fe60Pt25B15 alloy the amorphous phase coexists with an fcc FePt disordered solid solution. Differential scanning calorimetry curves of both alloys reveal a single exothermal peak with onset temperatures of 873 and 847 K for Fe60Pt15B25 and Fe60Pt25B15, respectively. Magnetically hard, tetragonal ordered L10 FePt and magnetically soft Fe2B nanocrystalline phases were formed due to the annealing of the alloys, as indicated by X-ray diffraction and Mössbauer spectroscopy measurements. Two-phase behavior was detected in the temperature dependence of magnetization of the annealed samples. A magnetic hardening was observed for all annealed ribbons. Magnetic properties of the annealed alloys, studied by hysteresis loop measurements, were related to the differences in the relative fractions of the hard and soft magnetic phases calculated from Mössbauer spectra. The alloy with 25 at% Pt exhibits better hard magnetic properties (Hc=437 kA/m, Mr/Ms=0.74) than the alloy with smaller Pt content (Hc=270 kA/m, Mr/Ms=0.73) mainly due to the larger abundance of the ordered tetragonal FePt phase. 相似文献
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The effect of IIIA metal and transition metalT substitution for Fe on crystal structure, magnetostriction and spontaneous magnetostriction, anisotropy and spin reorientation
of a series of polycrystalline Tb0.3 Dy0.7 (Fe0.9
T
0.1)1.95 (T=Mn, Fe, Co, B, Al, Ga) alloys at room temperature were investigated systematically. It was found that the primary phase of
the Tb0.3 Dy0.7 (Fe0.9
T
0.1)1.95 alloys is the MgCu2-type cubic Laves phase structure for different substitution. The magnetostriction λ{ins} decrases greatly for the substitution
of IIIA metal, B, Al and Ga, but is saturated more easily for Al and Ga substitution, showing that the Al and Ga substitution
is beneficial to a decrease in the magnetocrystalline anisotropy of Tb0.3 Dy0.7 (Fe0.9
T
0.1)1.95 alloys. However, the substitution of transition metal Mn and Co decreases slightly the magnetostriction λ{ins}. It was also
found that the effect of different substitutions on the spontaneous magnetostriction λ{in111} is distinct. The analysis of
the M?ssbauer spectra indicates that the easy magnetization direction in the {110} plane deviates slightly from the main axis
of symmetry for Al and Ga substitution, namely spin reorientation, but it does not change evidently for B, Mn and Co substitution. 相似文献
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B. W. Wang Z. D. Zhang S. L. Tang X. M. Jin X. G. Zhao 《Journal of magnetism and magnetic materials》1997,170(3)
Structure, Curie temperature and magnetostriction of RFex (1.6 x 2.0) and R(Fe1−yTiy)1.8 (y 0.2) alloys (R=Dy0.65Tb0.25Pr0.1) have been investigated using optical microscopy, X-ray diffraction, AC initial susceptibility and standard strain gauge techniques. The homogenized RFex alloys are found to be essentially single phase in the range of 1.8 x 1.85. The second phase is a rare-earth-rich phase when x 1.8, and (Dy, Tb, Pr)Fe3 phase when x 1.85. X-ray diffraction indicates that the R(Fe1−yTiy)1.8 alloys contain a small amount of Fe2Ti phase when y 0.05, which increases with the increment of Ti content. The Curie temperature of R(Fe1−yTiy)1.8 alloys slightly enhances with increasing Ti concentration when y 0.05, then remains almost unchanged in the range of 0.05 y 0.20. The magnetostriction of RFex alloys is improved when x 1.80 and reduced by increasing Fe content when x 1.85. The magnetostriction of R(Fe1−yTiy)1.8 alloys is lowered by increasing Ti content. 相似文献