Ti50Ni50—xPdx合金的高温形状记忆特性

以有关ＴｉＮｉＰｄ合金文献的实验数据为基础,总结Ｔｉ５０Ｎｉ５０－ｘＰｄｘ合金的相变温度与组分的关系,确定Ｔｉ５０Ｎｉ５０－ｘＰｄｘ合金的相变过程,并简要分析影响合金形状记忆效应的有关因素。     

Room Temperature Ferromagnetism in Ni Doped ZnO Powders

Zn_1−x Ni _x O (x=0.1%, 0.4%, 0.7%, 1.0%) powders were prepared using the sol-gel technique, and the structural, optical, and magnetic properties of the samples were investigated. X-ray diffraction measurements show that all samples have a wurtzite structure and that the c-axis lattice constant decreases as the Ni content increases. X-ray photoelectron spectroscopy studies reveal that the doped Ni ions are in divalent states in all samples. Optical absorption spectra show that the band energy of Zn_1−x Ni _x O powders decreases with increasing Ni concentration. Photoluminescence measurements of Zn_1−x Ni _x O show a broad peak at a wavelength centered at about 467 nm which indicates the presence of a fraction of defects in ZnO. The room temperature ferromagnetism observed in all samples is intrinsic in nature.     

Further Analysis of the Quantum Critical Point of Ce1-x La x Ru2Si2

New data on the spin dynamics and the magnetic order of Ce_1-xLa_xRu₂Si₂ are presented. The importance of the Kondo effect at the quantum critical point of this system is emphasized from the behavior of the relaxation rate at high temperature and from the variation of the ordered moment with respect to the one of the Néel temperature for various x.     

Ferromagnetism in One Layer of Self-organized InMnAs Quantum Dots

One layer of self-assembled InMnAs quantum dots with InGaAs barrier was grown on high-resistivity (100) p-type GaAs substrates by molecular beam epitaxy (MBE). A presence of ferromagnetic structure was confirmed in the InMnAs dilute magnetic quantum dots. The one layer of self-assembled InMnAs quantum dots was found to be semiconducting, and have ferromagnetic ordering with a Curie temperature, T _C =80 K. It is likely that the ferromagnetic exchange coupling of sample with T _C =80 K is hole-mediated resulting in Mn substituting Ge. PL emission spectra of InMnAs samples grown at temperature of 210°C and 285°C show that the interband transition peak centered at 1.31 eV comes from the InMnAs quantum dot.     

Controlling the Critical Temperature in Mg1−x Al x B2

Here we report synthesis and characterization of high quality samples of the superconducting system Mg_1−x Al _x B₂, with a novel optimized preparation method, in a wide range of Al concentration. All the physical properties of the samples can be tuned continuously with increasing Al content. We have characterized the samples for their structural, morphological and magnetic properties with high resolution XRD, SEM-EDS and susceptibility measurements. We have prepared a large number of Al doped MgB₂ in the range 0<x<0.57. All the samples are bulk superconductors and the critical temperature show a smooth and regular behavior as a function of x. This work was supported by European project 517039 “Controlling Mesoscopic Phase Separation” (COMEPHS) (2005). An erratum to this article can be found at     

铁基合金激光熔覆组织及其冲击磨损性能

利用ＡＴＥＭ研究了铁基合金Ｆｅ－Ｃｒ－Ｗ－Ｎｉ－Ｃ（ｗ（％）为１０：５：１：１：１）激光熔覆组织的相结构特征及高温时效时亚稳相转变过程。     

Magnetic properties of Ni1−x Cu x Cr2O4(0⩽x⩽1) compounds

The compounds Ni_1−x Cu _x Cr₂O₄ (0⩽x⩽1) have been synthesised by solid-state reaction between basic nickel(II) carbonate, basic copper(II) carbonate and chromium (III) carbonate in required molar ratios at 800±10°C for 20 hr. The reaction products have been characterized by chemical analyses and powder x-ray diffraction patterns. Magnetic susceptibility has been measured in the temperature range of 300–900 K at 10 kOe. All the products show ferrimagnetic behaviour with the ferrimagnetic Curie temperature (T _c) in the range of 50–150 K. The curie temperature increases when copper(II) ion is substituted for nickel(II) ion in NiCr₂O₄. The experimental values of the average effective magneton number (p-0304;) agree with theoretical values.     

机械合金化Fe100—xNix系超细粉末的X射线衍射谱研究

用机械合金化方法制备了Ｆｅ１００－ｘＮｉｘ系超细粉末（其中ｘ＝７５,４５,３５,３２．５,３０）。对各样品进行了Ｘ－ｒａｙ衍射谱测量,用Ｓｃｈｅｒｒｅｒ方法测量了晶粒尺寸。用最小二乘法计算了随Ｎｉ含量ｘ的减少样品晶格常数的变化以及随Ｘ的减少样品的结构变化。发现当Ｘ＝７５．４５时,样品成为以Ｎｉ为溶剂Ｆｅ为溶质的面赠立方固溶体,随着Ｆｅ含量不断增加,Ｆｅ－Ｎｉ合金中除了Ｎｉ型面心立方结构外,还存在α     

Quantum Isobaric Process in Ni2

Using the excited electronic states of Ni₂, we numerically build isobaric processes starting from different bond lengths and initial temperatures. Due to the complexity of the electronic structure of Ni₂, the isobaric processes can only be realized within a certain range of bond lengths. During each process the spin moment of the dimer decreases with increasing temperature. The work and the heat involved in the processes are also calculated.     

Transformation of Magnetic State under the Influence of Superconductivity in Epitaxial V/Pd1−x Fe x Bilayers

We have performed ferromagnetic resonance (FMR) studies of epitaxial V/Pd_1−x Fe _x (001) bilayers with a V thickness of the order of 40 nm and with a Pd_1−x Fe _x thickness in the range from 0.8 to 4.4 nm. For a bilayer with a Pd_1−x Fe _x thickness of 1.2 nm and x = 0.03, the FMR measurements revealed a decrease in the effective magnetization 4πM _eff of the ferromagnetic layer below the superconducting transition temperature of vanadium. As a possible explanation for this decrease, we suggest a spatial modulation of the ferromagnetic order in the Pd_1−x Fe _x layer due to modifications of the indirect exchange interaction of magnetic ions via conduction electrons in the superconducting state. A comparison with a recent theoretical investigation supports this possibility.     

B含量对非晶态Ni_（72－x）Si_（15）B_（13＋x）（X＝0，2，4，6，8）合金脆化温度的影响

通过试验研究了非晶态Ｎｉ７２－ｘＳｉ１５Ｂ１３＋ｘ（Ｘ＝０，２，４，６，８）合金脆化温度与Ｂ原子浓度的关系。根据双层结构单元模型和结构缺陷形成机制，分析了该合金的晶化过程，并对其试验结果进行了初步的解释。     

Irreversible enthalpy relaxation of amorphous (Fe1−x Ni x )83P17(x=0–1) alloys

This paper deals with the changes in exothermic enthalpy relaxation behaviour and Curie temperature of amorphous Fe₃₃Ni₅₀P₁₇ alloy upon annealing, and the compositional effect (i.e. the change with Fe/Ni ratio) on the magnitude of exothermic reactions during continuous heating of (Fe_1–x Ni _x )₈₃P₁₇ (x=0–1) alloys, in order to clarify the thermal relaxation behaviour with irreversibility of metal-metalloid type amorphous alloys. For Fe₃₃Ni₅₀P₁₇ alloy, the exothermic reaction showed two distinctive peaks at about 480 and 580 K and the low-temperature peak had a very strong correlation with the change in Curie temperature. Furthermore it was observed that for (Fe_1–x Ni _x )₈₃P₁₇ alloys the magnitude of the low-temperature peak was nearly proportional to the number of Fe-Ni atom pairs. However, the high-temperature one was almost independent of the changes in Curie temperature and the ratio of Fe to Ni. These results suggest that the exothermic enthalpy relaxation peak at temperatures far below T _g (or T _x) originates from the local rearrangement of metal-metal interactions of different species, while the high-temperature peak is due to the rearrangement of metal-metalloid bonding. This separation into two stages is interpreted as due to the difference of bonding forces between metal-metal and metal-metalloid pairs in amorphous Fe-Ni-P alloys.     

Characterization of Li1−x Ni1+x O2 prepared using succinic acid as a complexing agent

Li_1−x Ni_1+x O₂ was prepared by a polymerized complex method using succinic acid as a complexing agent. Ethanolic solutions of lithium acetate dihydrate, nickel acetate tetrahydrate, and succinic acid were mixed to form carboxylate precursors, which were subsequently calcined at 650–800°C for 14–48 h. TGA curves of metal acetates, succinic acid, and the precursors were characterized to determine weight loss and formation temperature of the oxide. By using XRD, SEM, and EDX, pure crystals of Li_1−x Ni_1+x O₂ were detected at 750 and 800°C. The maximum and minimum intensity ratios of XRD spectra show that the optimum calcination condition is 750°C for 40 h. At 650–800°C, the particle size distribution is in the range of 0.35–39 μm. The text was submitted by the authors in English.     

Anisotropy of the normal state properties of the superconducting Co1−x Ni x Zr2 system

Anisotropic behavior of the normal state thermoelectric power, electrical resistivity, and magnetic susceptibility is reported for the superconducting Co_1–x Ni _x Zr₂ system.This research was supported by the U.S. Department of Energy under Contract Number EY-76-S-03-0034-PA227-3 (ZH, WAF, MBM) and by the National Science Foundation under Grant Number NSF/DMR77-08469 (ZF, DCJ).Deceased.     

Mg_(76-x)V_xTi_(12)Ni_(12)(x=4、8、12、16)合金制备与贮氢性能的研究

采用机械合金化制备了Mg76-xVxTi12Ni12(x=4、8、12、16)合金,通过X射线衍射(XRD)、扫描电子显微镜(SEM)和压强-成分-温度(PCT)等分析方法对合金粉末进行分析和表征。结果表明,合金相主要由Mg2Ni相和Ti2Ni相组成,Mg76-xVxTi12Ni12(x=4、8、12、16)合金贮氢量(质量分数,下同)分别为3.71%、3.12%、2.85%和2.33%,随着V含量的增加,合金的贮氢量下降,合金氢化物释氢率分别为95.1%、97.1%、84.9%和94.4%,适量的V能提高合金氢化物的释氢率。     

Structure, morphology and magnetic properties of Mg((x))Zn((1 - x))Fe2O4 ferrites prepared by polyol and aqueous co-precipitation methods: a low-toxicity alternative to Ni((x))Zn((1 - x))Fe2O4 ferrites

The synthesis and properties of Mg((x))Zn((1 - x))Fe(2)O(4) spinel ferrites as a low-toxicity alternative to the technologically significant Ni((x))Zn((1 - x))Fe(2)O(4) ferrites are reported. Ferrite nanoparticles have been formed through both the polyol and aqueous co-precipitation methods that can be readily adapted to industrial scale synthesis to satisfy the demand of a variety of commercial applications. The structure, morphology and magnetic properties of Mg((x))Zn((1 - x))Fe(2)O(4) were studied as a function of composition and particle size. Scanning electron microscopy images show particles synthesised by the aqueous co-precipitation method possess a broad size distribution (i.e. ～ 80-120 nm) with an average diameter of the order of 100 nm ± 20 nm and could be produced in high process yields of up to 25 g l(-1). In contrast, particles synthesised by the polyol-based co-precipitation method possess a narrower size distribution with an average diameter in the 30 nm ± 5 nm range but are limited to smaller yields of ～ 6 g l(-1). Furthermore, the polyol synthesis method was shown to control average particle size by varying the length of the glycol surfactant chain. Particles prepared by both methods are compared with respect to their phase purity, crystal structure, morphology, magnetic properties and microwave properties.