金属玻璃在磁场张力退火时感生磁向各异性、磁致伸缩和应变的变化

本文通过同时测量金属玻璃Co_65.2Fe_4.2Ni₃Nb₁Al₂Si_9.8B_14.8的同一样品在各种横磁张力退火后的磁各向异性、磁致伸缩和应变,对这些物理量的变化情况作了比较。应变感生各向异性和暂态蠕变的行为有某种相似性,但其间不存在对应或因果关系。磁化感生各向异性K_um,应变感生各向异性K_us,饱和磁致伸缩常 关键词：     

金属玻璃(Fe1-xCox)78Si10B12的感生各向异性

本文研究了金属玻璃(Fe_1-xCO_x)₇₈Si₁₀B₁₂的磁化感生各向异性、应变感生各向异性随成分和温度的变化。磁化感生各向异性常数K_um为正值,x=0.7时为最大;不可逆的应变感生各向异性常数K_usi为正值,x=0.5时为最大;可逆的应变感生各向异性常数K_usr除了x>0.975区均为负值,在x=0.7时为最大;感生各向异性常数在温度变化时与M_s^α成正比,α在3.4和7.5之间随成分和退火工艺而变化。用短程有序模型解释了部分实验结果。 关键词：     

非晶态软磁薄膜Fe90-xCoxZr10的平面霍耳效应和磁阻效应

本文研究了非易态软磁薄膜Fe_90-xCo_xZr₁₀的平面霍耳电压及磁阻随磁场方向、成分和温度的变化规律。采用通常的六探针法进行了测量。结果表明平面霍耳电压和磁阻分别满足经验公式V_y=pM²Isin2θ和△ρ=cM²cos2θ;并给出了V_y表达式中的常数项p正比于ρ²。此外,样品Co₉₀Zr₁₀和样品Fe₇₀Co₂₀Zr₁₀晶化前后的V_y变化正好相反,即富钴成分的样品晶化后,V_y增加,而富铁成分的样品V_y下降。 关键词：     

金属玻璃应变感生磁各向异性动力学研究

本文研究了零磁致伸缩金属玻璃Co_65.2Fe_4.2Ni₃Nb₁Al₂Si_9.8B_14.8的应变感生磁各向异性K_us发展的动力学。K_us随退火时间t_a的变化涉及宽的弛豫时间分布。对于440℃244MPa张力退火后的280—320℃155MPa等温张力退火,得到激活能ΔE=180—290kJ/mol而相应的指数前因子τ_o=10^-14-10^-22s的结果。 关键词：     

磁共振法研究(Fe1-xCox)84Zr3.5Nb 3.5B8Cu1纳米晶薄带的磁各向异性

铁磁共振（FMR）实验研究(Fe_1-xCo_x)₈₄Zr_{3.5 Nb3.5B8Cu1（x=0.0,0.2,0.4,0.6, 0.8）合金薄 带的各向异性，易轴在薄带的横向方向,同等宽度样品 的各向异性常数K′随Co掺杂量的增加而减小, K′值在4.67×10^-5　J/m（x=0. 0）到 2.54×10^-5　J 关键词： 铁磁共振 各向异性常数 低场非共振信号 磁化过程}     

B元素添加对Co-Zr-Mo合金薄带的磁性能及结构的影响

利用X射线和磁性测量研究了Co_77Zr（18-x）Mo₅B_x合金薄带的结构和磁性.实验发现,在Co-Zr-Mo合金中添加适当含量的B,可以使其矫顽力显著提高,当x=2.0时,制备出具有迄今为止Co-Zr基永磁合金最大矫顽力H_c=7.0 kOe（1 Oe=79.5775 A/m）的快淬薄带.随着B元素添加,Co₇₇Zr_18-xMo₅B_x合金薄带的晶粒逐渐细化,并根据Henkel plot模型计算得出软磁相fcc-Co与硬磁相Co₅Zr相之间的交换耦合作用逐渐增强.合金薄带的矫顽力主要受硬磁相Co₅Zr相的晶粒尺寸控制,并随着晶粒尺寸的减小先升高后降低.另一方面,Co₇₇Zr₁₈Mo₅合金薄带的矫顽力机理为反磁化核形核模型,添加B元素之后矫顽力机理变为畴壁钉扎模型.通过X射线衍射和热磁分析发现,B元素并没有进入到Co₅Zr相的晶格中,而是存在于非晶相中.     

非晶态Co70Cr20Zr10合金在居里温度附近的磁性

本文研究非晶态Co₇₀Cr₂₀Zr₁₀合金在居里温度附近的磁性,样品的磁特性符合二级相变规律。得到临界指数β=0.45±0.02,γ=1.9±0.1,δ=5.13±0.05。Co₇₀Cr₂₀Zr₁₀合金的居里温度为T_c=(186.7±0.2)K。临界指数β,γ,δ满足γ=β(δ-1)关系,但临界指数值都偏离三维Heisenberg模型的理论值,这种行为可能起源于非晶态合金磁的不均匀性。讨论了Kouvel-Fisher(K-F)参数γ(T)对温度T的依赖关系。 关键词：     

Ta对C—15相V2Hf和V2(Zr0.5Hf0.5)系列声子性能的影响

本文用中子飞行时间方法对C-15相的超导材料V₂Hf,V₂Ta和V₂Hf_0.8Ta_0.2以及V₂Zr_0.5。Hf_0.5和V₂Zr_0.5Hf_0.33Ta_0.17的热中子非弹性散射谱作了测量,并计算出相对的广义声子态密度。结果与早先发表的Nb对C-15相V₂Zr和V₂(Hf_0.5Zr_0.5)系列声子性能的影响一致:声子频率随超导转变温度T_c增加而软化,随T_c减小而硬化。这表明,对于此类材料弹性软化在一定程度上对提高T_c起了作用。结果还进一步表明V₂Zr或V₂Hf与V₂(Zr_0.5Hf_0.5)之间有着质的差别,V₂Hf加Ta后,T_c增加,声子频率软化,而V₂(Zr_0.5Hf_0.5)加Ta后,T_c减小,声子频率则略有硬化。这与V₂Zr和V₂(Hf_0.5Zr_0.5)加Nb的结果是一致的。此结果可以用角动量分波表象的能带论方法分析电-声耦合相互作用得出的杂化理论来定性解释。 关键词：     

氢稀释对多晶硅薄膜结构特性和光学特性的影响

以SiCl₄和H₂为气源，用等离子体增强化学气相沉积技术，在250℃的低温下，研究氢稀释度对多晶硅薄膜结构特性的影响.实验结果表明，对于以SiCl₄和H₂组成的反应源气体，氢对薄膜生长特性的影响有异于SiH₄/H₂，在一定功率下，薄膜的晶化率随氢稀释度的减小而增加，在一定的氢稀释度下薄膜晶化度达到最大值85％；随着氢稀释度的继续减小，薄膜晶化度迅速下降，并逐渐向非晶态结构转变.随氢稀释度的减小，薄膜的光学带隙由 1.5eV减小至约1.2eV，而后增大至1.8eV.沉积速率则随氢稀释度的减小先增加后减小，在无氢条件下，无薄膜形成.在最佳氢稀释度条件下，Cl基是促进晶化度提高，晶粒长大的一个主要因素. 关键词： 多晶硅薄膜 微结构 氢稀释 4')" href="#">SiCl₄     

界面对Fe65Co35薄膜微结构和软磁性的影响

用不同的材料（Co₉₃Fe₇和Fe）作衬底层,利用磁控溅射法成功制备了Fe₆₅Co₃₅（主层）/衬底层结构的双层薄膜．通过X射线衍射和磁性测量发现,在不同的衬底上沉积的Fe₆₅Co₃₅薄膜的织构不同,并且（200）取向的Fe₆₅Co₃₅薄膜的面内各向异性和软磁性优于（110）取向的Fe₆₅Co_{35关键词： 65}Co₃₅薄膜')" href="#">Fe₆₅Co₃₅薄膜 衬底层 界面各向异性 软磁性     

Charge transport mechanism in thin films of amorphous and ferroelectric Hf0.5Zr0.5O2

The charge transport mechanism in thin amorphous and ferroelectric Hf_0.5Zr_0.5O₂ films has been studied. It has been shown that the transport mechanism in studied materials does not depend on the crystal phase and is phonon-assisted tunneling between traps. The comparison of the experimental current–voltage characteristics of TiN/Hf_0.5Zr_0.5O₂/Pt structures with the calculated ones provides the trap parameters: thermal energy of 1.25 eV and the optical energy of 2.5 eV. The trap concentration has been estimated as ~10¹⁹–10²⁰ cm^–3.     

Effect of nanoparticle size on magnetic damping parameter in Co92Zr8 soft magnetic films

Co₉₂Zr₈(50 nm)/Ag(x) soft magnetic films have been prepared on Si (111) substrates by oblique sputtering at 45°. Nanoparticle size of Co₉₂Zr₈ soft magnetic films can be tuned by thickening Ag buffer layer from 9 nm to 96 nm. The static and dynamic magnetic properties show great dependence on Ag buffer layer thickness. The coercivity and effective damping parameter of Co₉₂Zr₈ films increase with thickening Ag buffer layer. The intrinsic and extrinsic parts of damping were extracted from the effective damping parameter. For x=96 nm film, the extrinsic damping parameter is 0.028, which is significantly larger than 0.004 for x=9 nm film. The origin of the enhancement of extrinsic damping can be explained by increased inhomogeneity of anisotropy. Therefore, it is an effective method to tailor magnetic damping parameter of thin magnetic films, which is desirable for high frequency application.     

Crystallization behavior and microstructure of Fe75Co6Zr9B10 alloy

Fe₇₅Co₆Zr₉B₁₀ amorphous alloy prepared by melt-spinning was annealed at various temperatures. The crystallization behavior and microstructure were investigated by differential thermal analysis (DTA), X-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The three exothermal peaks in the DTA curve of Fe₇₅Co₆Zr₉B₁₀ amorphous alloy correspond to the formations of α-Fe and α-Mn type phases, the growth of BCC-Fe volume fraction at the expense of α-Mn and residual amorphous phase and the precipitations of Fe₃Zr, etc. intermetallic compounds, respectively. The second exothermic peak is not influenced by heating rate, but it shifts to a higher temperature region with increasing preannealing temperature of Fe₇₅Co₆Zr₉B₁₀ alloy. The α-Mn type phase is metastable and its lattice parameter determined by TEM is 0.8830 nm. AFM images show the development of surface morphology of alloy after annealing. The particle size increases with increasing annealing temperature.     

Magnetic after-effects of hydrogen in amorphous Co75Si15B10 alloys

The magnetic after-effect spectrum of hydrogen-charged amorphous Co₇₅Si₁₅B₁₀ and its annealing behaviour was measured in the temperature range between 2.1 and 450 K. A hydrogen related relaxation peak was observed at 190 K with a mean activation energy of 0.42 eV.     

Modification of the saturation magnetostriction constant after thermal treatments for the Co58Fe5Ni10B16Si11 amorphous ribbon

A new method for measuring the magnetostriction constant has been developed. The resolution of this sensitive method allows to measure values of that constant as low as 10^-9. It has been found that after thermal treatments, the magnetostriction constant of the amorphous ribbon whose nominal composition is Co₅₈Fe₅Ni₁₀B₁₆Si₁₁ changes not only its absolute value but also its sign. The kinetics of this variation has also been studied and a mean value of the activation energy of 0.8 eV for the relaxation process was obtained. Such variations of the magnetostriction constant are discussed as produced by modifications of the short-range order during annealing.     

Variation of magnetic state of amorphous Fe90Zr10 and Fe91Hf9 by the charge of hydrogen

Amorphous Fe₉₀Zr₁₀ and Fe₉₁Hf₉ ribbons were charged with hydrogen by the electrochemical method up to Fe₉₀Zr₁₀H₂₆ and Fe₉₁Hf₉H₁₅, respectively, and the change in magnetic structures were analyzed by Mössbauer spectrometry. The internal magnetic field appeared by the charge of hydrogen, the degree of change being depended on amounts of hydrogen included in amorphous Fe₉₀Zr₁₀ and Fe₉₁Hf₉, although Fe₉₁Hf₉ absorbed hydrogen more slowly than Fe₉₀Zr₁₀. The differences of hydrogen inclusion and Mössbauer hyperfine structure between Fe₉₀Zr₁₀ and Fe₉₁Hf₉ were discussed based on the results of a hyperfine field distribution and the radial distribution functions of Fe?Fe obtained by EXAFS.     

Effect of composition and thermal annealing on the absorption and electrical conduction of Se85−xTe15Sbx glasses

The optical absorption of the as-prepared and thermally annealed Se_85−xTe₁₅Sb_x (0≤x≤9) thin films was measured. The mechanism of the optical absorption follows the rule of non-direct transition. The optical energy gap (E₀) decreased from 1.12 to 0.84 eV with increasing Sb content of the as-prepared films from 0 to 9 at.%. The as-prepared Se₇₆Te₁₅Sb₉ films showed an increase in (E₀) with increasing the temperature of annealing in the range above T_g (363 K). The electrical conductivity of the as-prepared and annealed films was found to be of Arrhenius type with temperature in the range 300-360 K. The activation energy for conduction was found to decrease with increasing both the Sb content and temperature of annealing. The results were discussed on the basis of the lone-pair electron effect and of amorphous crystalline transformation.     

Structure and magnetic properties of iron-and cobalt-based amorphous alloys versus nanocrystallization conditions

The effect of the structural state of Fe₅Co₇₀Si₁₅B₁₀, Fe₆₀Co₂₀Si₅B₁₅, and Co_81.5Mo_9.5Zr₉ amorphous alloys on their magnetic properties is studied under different nanocrystallization conditions. A permanent magnetic field applied during thermomagnetic treatment is found to affect structuring in the amorphous alloys at the initial stage of devitrification. The fine structure of the devitrified amorphous alloys is shown to correlate with the field shifting the hysteresis loop. A mechanism accounting for a hysteresis loop shift in amorphous alloys is discussed.     

Structural,optical and electrical properties of laser irradiated Pb doped Ga–Se chalcogenide thin films

Using the Transverse Electrical Excitation at Atmospheric Pressure (TEA) nitrogen laser, we had irradiated the amorphous thin films of Ga₁₀Se₈₁Pb₉ chalcogenide glass and the results have been discussed in terms of the structural aspects of Ga₁₀Se₈₁Pb₉ glass. The observed changes are associated with the interaction of the incident photon and the lone-pairs electrons which affects the band gap. The X-ray structural characterization revealed the amorphous nature of as prepared films and polycrystalline nature of the laser irradiated films. The optical band gap of these thin films is measured by using the absorption spectra as a function of photon energy in the wavelength region 400–1200 nm. It is found that the optical band gap decreases while the absorption coefficient increases with increasing the irradiation time. The decrease in the optical band gap has been explained on the basis of change in nature of films, from amorphous to polycrystalline state, with the increase in exposure time. The dc conductivities and activation energies of these thin films are measured in temperature range 303–403 K. It has been found that the activation energy in Ga₁₀Se₈₁Pb₉ chalcogenide thin films decreases whereas the dc conductivity increases at each temperature by increasing the irradiation time.     

Structural-optical study of high-dielectric-constant oxide films

High-k polycrystalline Pr₂O₃ and amorphous LaAlO₃ oxide thin films deposited on Si(0 0 1) are studied. The microstructure is investigated using X-ray diffraction and scanning electron microscopy. Optical properties are determined in the 0.75-6.5 eV photon energy range using spectroscopic ellipsometry. The polycrystalline Pr₂O₃ films have an optical gap of 3.86 eV and a dielectric constant of 16-26, which increases with film thickness. Similarly, very thin amorphous LaAlO₃ films have the optical gap of 5.8 eV, and a dielectric constant below 14 which also increases with film thickness. The lower dielectric constant compared to crystalline material is an intrinsic characteristic of amorphous films.