材料期刊网

STUDY OF THE INJURY OF THE Ar+ INJECTION Si LAYER BY THE USE OF XRD AND ELLIPSOMETER

G.Q.Wang , F.F.Jiang and X.N.Wang Basic Lessons Department , Shengyang University , Shengyang 110044 , China

金属学报(英文版)

The Ar+ injection layer into silicon can be described as inhomogeneous absorption medium wafer. The distribution of the stress, strain, strain energy in the injury layer has been studied utilizing XRD. And the average ellipsometer is used here to investigate the optical constant and degree of injury of the ion injection injury wafer.

关键词: XRD , null , null , null

Superconductivity modulated by internal pressure in Ce(1-x)Gd(x)FeAsO(0.84)F(0.16) compounds

Superconductor Science & Technology

It is shown that the superconductivity in Ce(1-x)Gd(x)FeAsO(0.84)F(0.16) compounds can be modulated by internal (chemical) pressure. The internal pressure is induced by Gd substitution for Ce in CeFeAsO(0.84)F(0.16), which compresses the crystal lattice. The temperature dependences of resistivity and magnetization show that the superconducting-transition temperature T(c) is enhanced from 40 K for CeFeAsO(0.84)F(0.16) to 47.5 K for Ce(0.6)Gd(0.4)FeAsO(0.84)F(0.16). The increase and subsequent decrease of Tc upon application of external pressure, as observed previously in LaFeAsO(0.89)F(0.11), is entirely confirmed by the modulation of Tc of the Ce(1-x)Gd(x)FeAsO(0.84)F(0.16) superconductors by internal pressure.

关键词: layered quaternary compound;43 k;iron

Structural evolution of Ce(1-x)Gd(x)FeAsO(0.84)F(0.16) superconductors

Journal of Applied Physics

Structural parameters have a critical impact on superconductivity in iron-based oxypnictide superconductors. Structural evolution study was performed on Ce(1-x)Gd(x)FeAsO(0.84)F(0.16) superconductors by the analysis of the x-ray diffraction patterns with Rietveld refinement. Substitution of Gd for Ce generates internal pressure that compresses the crystal lattice. The contraction of the c axis is also indicated by the reduction of Ce/Gd-As and Ce/Gd-O/F distances, while there is a slight increase in the As-Fe-As block size, which is compensated by a large reduction in the Ce/Gd-O/F-Ce/Gd block with Gd substitution. The diagonal Fe-As-Fe angle for Ce(0.6)Gd(0.4)FeAsO(0.84)F(0.16), with the highest T(c) among Ce(1-x)Gd(x)FeAsO(0.84)F(0.16) compounds, is 111.13 degrees. It is close to the ideal value of 109.47 degrees for the perfect FeAs tetrahedron, which is situated in the region of Fe-As-Fe bond angles where RFeAsO compounds tend to have the highest T(c). (C) 2011 American Institute of Physics. [doi:10.1063/1.3565408]

关键词: layered quaternary compound;high-temperature superconductivity

GdFeAsO_(1-x)F_x超导体的制备及其超导电性

崔雅静 , 陈永亮 , 杨烨 , 王雅真 , 张勇 , 赵勇

低温物理学报

通过先制备一种纳米尺寸的GdF_3作为GdFeAsO_(1-x)F_x样品中F的反应原料,在相对较低的温度(1120℃)下成功制备出一系列GdFeAsO_(1-x)F_x(x=0,0.05,0.1,0.15,0.2,0.25)多晶样品.X射线衍射结果表明,超导样品属四方ZrCuSiAs-type结构,晶格参数随着掺F量的增加而减小.扫描电子显微镜测试结果表明,样品具有片层状晶体形貌特征.当掺F量x=0.1时,样品表现出超导电性,超导转变温度为22K,随着掺F量的增多,超导转变温度升高.和其他制备方法相比,这种制备方法更有利于F的掺入,而且可有效减少样品中杂质相的含量.

关键词: 铁基超导体 , ZrCuSiAs结构

源气体流量比对a_C:F:N薄膜的影响

张云芳

材料科学与工程学报 doi:10.3969/j.issn.1673-2812.2006.04.036

以CF4、CH4和N2的混合气体为源气体,利用rf-PECVD沉积技术制备了氮掺杂氟化非晶碳(a_C:F:N)薄膜,研究了源气体流量比对a_C:F:N薄膜沉积速率和结构的影响.用椭圆偏振光谱测试仪测量了薄膜厚度,结合沉积时间计算了薄膜的沉积速率(在18～21nm/min之间),随流量比增大,薄膜的沉积速率先升高后降低.FTIR光谱分析表明,随流量比增大,薄膜中含F量降低,交联结构增强.Raman光谱分析发现,薄膜中的碳原子由sp2和sp3两种组态的混合结构组成,并进一步证明,随流量比增大,薄膜中sp2键含量增加,交联程度增强.

关键词: 流量比 , 氮掺杂氟化非晶碳薄膜 , 拉曼光谱

Si₃N₄/BN_(f)复合材料的相界面

许钫钫 , 宋澄宇 , 温树林 , 马利泰

无机材料学报

本文借助高分辨电子显微镜研究了Si₃N₄／BN（f）复合材料的相界面,研究发现，BN纤维的两端与基体结合牢固，界面不易解离，材料断裂过程中纤维很难拔出．材料的韧性主要通过BN纤维自身（001）面上的滑移、撕裂和弯曲以及BN纤维的侧表面与Si₃N₄颗粒的界面上的解离等途径得以提高．

关键词: BN纤维 , composite , interfaces , microstructure

TiAl与Si3N4f/Si3N4复合材料钎焊接头界面结构及性能研究

宋晓国 , 曹健 , 王义峰 , 冯吉才

稀有金属材料与工程

采用AgCuTi钎料实现了TiAl与Si3N4f/Si3N4复合材料的钎焊,确定了钎焊接头的典型界面组织结构为TiAl/AlCuTi/Ag(s,s)/TiN/Si3N4f/Si3N4.钎焊过程中,液相钎料在Si3N4f/Si3N4复合材料表面发生较好润湿,钎料中活性元素Ti与Si3N4基体及纤维发生反应形成连续的TiN化合物层.过高的钎焊温度或过长的保温时间导致钎缝中脆性的AlCuTi化合物增加,且由于接头应力的作用在钎缝中产生微裂纹甚至开裂,严重地降低了钎焊接头性能.当钎焊温度T=850℃,保温时间为10 min时,接头抗剪强度达到最大,为9.4 MPa,超过Si3N4f/Si3N4母材层间抗剪强度的60％.断口分析表明:压剪过程中,断裂发生在Si3N4f/Si3N4复合材料一侧.

关键词: TiAl , Si3N4f/Si3N4复合材料 , AgCuTi钎料 , 界面结构 , 钎焊

非金属元素C、N、F掺杂锐钛矿型TiO2的缺陷形成能和电子性质

岳远霞 , 冯庆 , 王寅

功能材料 doi:10.3969/j.issn.1001-9731.2013.13.014

非金属杂质掺杂TiO2半导体改善对可见光区域的光催化性质是近年来的一个研究热点,但相关杂质缺陷的形成能研究却不多.通过基于密度泛函理论的平面波超软赝势方法,研究了非金属元素C、N、F掺杂锐钛矿型TiO2之后的缺陷形成能与电子性质.结果表明,3种元素掺杂进入TiO2后缺陷形成能的大小排序为C＞N＞F,说明F元素最容易掺杂进入TiO2晶格.但是掺入F元素后对TiO2禁带宽度的改变不大,在提高TiO2对可见光的响应方面F元素的效果不如N、C两种元素.因此,对于掺杂来改善TiO2对可见光的响应方面,N元素比C、F的效果更好.

关键词: 第一性原理 , 密度泛函理论 , C,N,F掺杂 , 缺陷形成能 , 电子性质

适用钛不同焦距X射线照相用的KUP-T-F曝光曲线

魏惠元

稀有金属材料与工程

介绍了可适用钛金属0.4 m～1.2 m不同焦距、微粒胶片X射线照相用的KUPTF新型曝光曲线的制作原理及方法.试验结果表明,新型曝光曲线具有制作简便、经济实用、可兼顾底片象质和拍片效率的优点,是钛制压力容器现场变焦距透照选取准确管电压值的理想工具.

关键词: 钛 , X射线照相 , KUPTF , 曝光曲线

Investigations of EPR g Factors and Rhombic Distortion for the Rhombic Cu2+ Centers in K2Zn1-x Cu (x) F-4 Crystals at Low Temperature

Applied Magnetic Resonance

The electron paramagnetic resonance g factors g (i) (i = x, y, z) of two rhombic Cu2+ centers, Cu2+(II) and Cu2+(III), in K2Zn1-x Cu (x) F-4 crystals found at low temperature are calculated from the complete diagonalization (of energy matrix) method based on the cluster approach. The calculations show that the ground state wave function of the two rhombically compressed Cu2+ centers is with a small admixture of . The rhombic distortions for both Cu2+ centers are obtained from the calculations. The results are discussed.

关键词: electron-paramagnetic-resonance;atomic screening constants;hyperfine;parameters;gyromagnetic factor;spin resonance;scf functions;field;copper(ii);dependence;spectra