Feasibility of study magnetic proximity effects in bilayer “superconductor/ferromagnet” using waveguide-enhanced polarized neutron reflectometry

A resonant enhancement of the neutron standing waves is proposed to use in order to increase the magnetic neutron scattering from a “superconductor/ferromagnet” (S/F) bilayer. The model calculations show that usage of this effect allows to increase the magnetic scattering intensity by factor of hundreds. Aspects related to the growth procedure (order of deposition, roughness of the layers etc.) as well as experimental conditions (resolution, polarization of the neutron beam, background etc) are also discussed. Collected experimental data for the S/F heterostructure Cu(32 nm)/V(40 nm)/Fe(1 nm)/MgO confirmed the presence of a resonant 60-fold amplification of the magnetic scattering.     

Neutron nano-spin-echo spectrometer based on magnetic nanostructures

A neutron spin-echo spectrometer based on spin precessors in the form of magnetic layered nanostructures is described. A model of a spin-echo spectrometer is developed on beam no. 9 in the IBR-2 reactor. In this model, spin precession occurs during motion of neutrons in a magnetic field and their double reflection from Al(30 nm)/Fe(15 nm)/Al(120 nm)/Cu(150 nm) magnetic layered structures. The obtained spectrometer parameters make it possible to investigate excitations in films with a wave vector oriented along the neutron beam direction in the range from 10^?3 to 10^?1 Å^?1 and perpendicularly to the beam in the range from 10^?4 to 10^?5 Å^?1.     

Kinematical limit in the theory of X-ray magnetic reflectivity

A kinematical approximation has been derived from the general formulas for calculating the reflectivity from a multilayer anisotropic structure. An explicit form of reflection matrices at the boundary of layers and the refraction tensors has been obtained for a particular case where the layer magnetization is oriented in the surface plane and for an arbitrary form of X-ray susceptibility tensors. Calculations of the reflectivity from a Nb(4 nm)/[Dy(5 nm)/Lu(3 nm)]₄₂₀ model structure with helicoidal ordering of Dy magnetic layers show that kinematical approximation can be applied for grazing angles that are larger than the critical total-reflection angle and that the “magnetic” refraction must be taken into account.     

Precision structural diagnostics of layered superconductor/ferromagnet nanosystems V/Fe by reflectometry and diffuse scattering of synchrotron radiation

Layered superconducting ferromagnetic nanosystems Cu(32 nm)/V(40–80 nm)/Fe(0.5–4 nm)/MgO(001) have been investigated by reflectometry and the diffuse scattering of synchrotron radiation. The data obtained make it possible to determine the important characteristics of samples such as the layer thickness and the rms heights and lateral correlation lengths of roughness at the interfaces.     

Determination of the magnetic contribution to the YFe2 susceptibility by means of X-ray resonant magnetic reflectivity

The reflectometry curves of an Nb(4 nm)/YFe₂(40 nm, 〈110〉)/Fe(1.5 nm)/Nb(50 nm) sample measured in the synchrotron radiation of right- and left-handed circular polarization for a set of wavelengths near the Y L _2,3 absorption edges have been used to determine the energy dependences of the component magnitudes for the X-ray susceptibility tensor of YFe₂ near the yttrium absorption edges, including off-diagonal magnetic additives. Our result is in good agreement with the normalized experimental absorption and circular dichroism spectra and their Kramers-Kronig transformations.     

TOPCon太阳电池发射极Al2O3/SiNx与SiO2/Al2O3/SiNx叠层膜钝化性能的比较

本文对TOPCon电池发射结的叠层钝化膜进行了研究,对比了3种不同叠层钝化膜(SiO₂/SiN_x、Al₂O₃(1.5 nm)/SiN_x、SiO₂/Al₂O₃(1.5 nm)/SiN_x)的钝化性能。结果表明:Al₂O₃(1.5 nm)/SiN_x的钝化性能优于SiO₂/SiN_x,SiO₂/Al₂O₃(1.5 nm)/SiN_x的钝化水平最佳,隐开路电压均值可达到705 mV。基于Al₂O₃/SiN_x叠层膜研究了Al₂O₃厚度(1.5 nm、3 nm和5 nm)对钝化性能和电池转换效率的影响。当Al₂O₃厚度由1.5 nm增加到3 nm时,钝化性能得到明显提升,隐开路电压均值提高了20 mV,达到707 mV,对应电池的光电转换效率升高了0.23个百分点,与SiO₂/Al₂O₃(1.5 nm)/SiN_x叠层膜电池的转换效率持平。然而,当Al₂O₃厚度继续增加至5 nm时,隐开路电压均值保持不变。因此可以使用Al₂O₃(3 nm)/SiN_x叠层膜代替SiO₂/Al₂O₃(1.5 nm)/SiN_x叠层膜,不仅简化了电池的工艺步骤,而且降低了生产成本。     

Blue electroluminescent materials based on indeno[1,2-a]arene derivatives for Organic Light-Emitting Diodes

Abstract

In this study, as a continuous effort for searching efficient blue-emitting materials, we designed and synthesized materials based on indeno[1,2-a]arene. OLED devices using these materials were fabricated in the following sequence; ITO (180?nm)/N,N'-diphenyl-N,N'-(2-napthyl)-(1,1'-phenyl)-4,4'-diamine (NPB) (50?nm)/emitting materials (30?nm)/4,7-diphenyl-1,10-phenanthroline (Bphen) (30?nm)/Liq/Al (2/100?nm). Particularly, a device using 7,7-dimethyl-7H-indeno[1,2-a]pyrene as emitter showed maximum values of luminous efficiency, power efficiency, and external quantum efficiency of 1.10?cd/A, 0.49?lm/W, 1.47% at 20?mA/cm², respectively with CIE (x,y) coordinates of (0.15, 0.08) at 6.0V.     

之字链配合物Cu(phth)2(H2O)2的合成、表征及晶体结构

用Cu(NO3)2·3H2O和phth(邻苯二甲酸)混合反应得到了配合物Cu(phth)2(H2O)2(1).通过元素分析、红外光谱对配合物进行了表征,用X射线单晶衍射仪测定了配合物的晶体结构.配合物为单斜晶系,P2(1)/c空间群.晶胞参数a=0.83895(17)nm,b=1.4441(3)nm,c=0.70992(14)nm,β=112.14(3)°,V=0.7967(3)nm3,Z=2,Dc=1.792 g/cm3,F(000)=438.0,S=1.100,R1=0.0376,wR2=0.0998.铜原子为四配位,呈畸变正方形构型,通过邻苯二甲酸根的π-π堆积作用形成了一维之字型链,相邻的链之间靠氢键和π-π堆积作用形成三维分子结构.     

MgZnO/ZnO异质结构的发光性质研究

本文利用等离子体辅助分子束外延(P-MBE)技术在蓝宝石 (Al2O3) 衬底上生长了Mg0.12Zn0.88O(100nm)/ZnO (20nm) /Mg0.12Zn0.88O (40nm) 异质结构,测得样品的X射线衍射谱表明,在34.56°的位置出现很强的(002)方向衍射峰,其半高宽度为0.20°,比Mg0.12Zn0.88O合金薄膜的半高宽度0.15°明显展宽.通过光致发光谱研究了MgZnO/ZnO/MgZnO异质结构的光学性质,室温下测得在370nm(3.35eV)位置有很强的紫外发光,而在348nm (3.56eV)的位置处有一个较弱的发光,这两个峰分别被归结于来自ZnO层和MgZnO盖层的发光.室温下的吸收光谱中,在上述两个峰的位置附近分别存在很明显的吸收,指示了带边吸收来自于MgZnO和ZnO两种材料.通过变温发光谱研究了异质结构中载流子弛豫、复合的规律.随着温度增加,来自于ZnO层和MgZnO层的发光强度比增加,这归结为MgZnO/ZnO异质结构存在界面势垒所致.     

无机-有机杂化晶体[C_(12)H_(11)N_2O_2][Cd(SCN)_3]的合成和晶体结构(英文)

合成了无机-有机杂化晶体[C12H11N2O2][Cd(SCN)3],并采用元素分析、红外光谱表征和单晶X射线衍射分析和热重分析研究.红外光谱分析表明SCN-采用1,3-μ模式.结构分析表明,相邻的Cd(II)原子通过三个1,3-μ-SCN- 阴离子桥连形成无限的[Cd(SCN)-3]∞之字链结构,固体结构中[C12H11N2O2]+阳离子和[Cd(SCN)-3]∞配阴离子形成了分离柱状堆积.该晶体属于单斜晶系P2(1)/c空间群,晶胞参数分别为:a = 1.1260(3) nm, b = 1.5080(4) nm, c =1.1070(3) nm, β= 105.410(10) °, V = 1.8121(8) nm3, Z = 4, dc = 1.840 g·cm3 , T = 293(2) K, μ = 1.571 mm-1, F(000) = 992, R1 = 0.0343, wR2 = 0.0750 [I>2σ(I)]. 热分析结果在180-305 ℃化合物失去一个有机分子,305 ℃以上伴随着镉升华失去三个SCN-阴离子.     

Organic Light-Emitting Diodes based on Benzo[q]quinoline Derivatives

Abstract

In this study, we synthesized two emitting materials based on benzo[q]quinoline derivatives. OLED devices using these materials were facricated in the following sequence;ITO(180nm)/4,4',4''-Tris[2-naphthyl(phenyl)amino]triphenylamine(2-TNATA)(30nm)/N,N'-di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine(NPB)(20nm)/Emitting materials(30nm)/4,7-diphenyl-1,10-phenanthroline (Bphen)(30nm)/Liq(2nm)/Al(100nm). Particularly, a device using 2,4-di(naphtalene-1-yl)benzo[q]quinoline as an emitter exhibited the efficient emission with a luminous efficiency, a power efficiency, and exteranl quantum efficiency of, and the CIE coordinates of 2.91cd/A, 0.99lm/W, 0.90% at 20mA/cm², and (0.33, 0.55) at 1000cd/m², respectively. Interestingly, emissions from electromers and electroplexes were shown to be crucial role in electroluminescences from benzo[q]quinoline derivatives     

陶瓷单晶(100)基底上外延生长Pt薄膜

用对靶溅射技术在MgAl2O4 (100) (MAO) 和SrTiO3 (100) (STO)单晶基底上制备Pt薄膜.基底温度为700℃时,Pt薄膜外延生长为(200)取向,Pt/STO 薄膜的电阻率很低,而Pt/MAO 薄膜表现出高电阻特征.此外,Pt (50nm)/La0.67Ca0.33MnO3 (50nm)/STO的制备和研究表明,在包括庞磁电阻材料的器件设计中,Pt是一种较好的电极材料.     

Characterization of the interaction between peptides derived from the gp120/V3 domain of HIV-1 and the amino terminal of the chemokine receptor CCR5 by NMR spectroscopy and light scattering

We applied static and dynamic light scattering (DLS) to probe the structural and physicochemical determinants of the interaction between the gp120 V3 domain of the human immunodeficiency virus HIV-1 and the amino terminal of the chemokine receptor CCR5 (CCR5-Nt). CCR5-Nt is a co-receptor that infectious HIV strains utilize to gain entry into target cells. Preventing HIV from interacting with these co-receptors prevents viral entry. In this study, we present the first systematic investigation of the size, shape, dynamics, and interactions of self-associating peptide complexes formed by a 13-residue peptide, V3 (from the strain MN), in dilute aqueous solution, using DLS. Nuclear magnetic resonance (NMR) spectra indicate that the free V3 and CCR5-Nt peptides as well as the V3-CCR5-Nt mixture are somehow structured in solution. Also, NMR spectra in combination with peptide titration suggest a weak interaction between the V3 domain and CCR5-Nt. Finally, the NMR data suggest monomeric or self-associating complexes amenable to NMR studies without significant spectral line broadening, for V3, CCR5-Nt, and the V3–CCR5-Nt complex. The monomers or self-associating complexes observed by NMR are not expected to be in exchange with the self-associating complexes observed by dynamic light scattering. Light scattering on exactly the same NMR samples confirms the presence of the complexes that were observed at lower concentrations.     

Full Permanent Memory Effect in PDLC Films

Permanent memory effect in polymer dispersed liquid crystal (PDLC) films prepared by thermal polymerization induced phase separation (PIPS) were studied. New trimethylolpropane trimethacrylate (TMP3MA)/poly(propylene glycol) methacrylate (PPGMA375)/E7/AIBN and pentaerythritol tetraacrylate (PE4A)/poly(propylene glycol) acrylate (PPGA475)/E7/AIBN PDLC films showed 86% permanent memory effect with E90 = 6 V/μm and memory state contrast of 70% and full permanent memory effect with E90 = 3 V/μm and total memory state contrast, respectively. These materials with two stable states (opaque and transparent) seem to be promising for the development of a new class of optical memories as they can be used for electrically write information, optically read the written information and they can be thermally erased back to the initial scattered state.     

Ti:Al2O3透明多晶陶瓷光谱特性分析

采用传统无压烧结工艺制备出透明性良好的掺Ti氧化铝陶瓷;测定了该陶瓷的吸收光谱、荧光光谱和激发光谱.结果表明,掺Ti氧化铝透明陶瓷样品在Mg与Ti掺入离子的摩尔比(NMg/NTi)较小时,表现出Ti3+离子的490nm特征吸收峰,即2T2→2E跃迁产生的宽带吸收;NMg/NTi较大时,陶瓷样品吸收光谱中不存在Ti3+离子吸收,其250nm处吸收为O2-→Ti4+的转移吸收.掺Ti氧化铝透明陶瓷样品Ti3+离子的发射谱线与单晶的相吻合,同时Ti3+在氧化铝陶瓷中分布很均匀,且Ti3+浓度较高时仍处于未畸变的八面体格位当中.氢气氛下烧结的陶瓷样品因MgO添加剂的存在而在410nm处产生Ti4+离子荧光发射;而280nm、420nm左右的荧光发射分别是由F+和F心造成的.     

Na3La2(BO3)3的晶体结构

以Na2CO3-H3BO3-NaF为助熔剂,使用顶部籽晶法生长出Na3La2(BO3)3透明单晶.测定了Na3La2(BO3)3的晶体结构,该晶体属正交晶系,空间群:mm2(No.38),晶胞参数为a＝0.51580(10)nm,b=1.1350(2)nm,c=0.73230(15)nm,α＝β＝γ＝90°,V＝0.42871(15)nm3,密度:.053g/cm3.晶体结构中的硼氧基团是平面的BO3基团,BO3基团相互独立,且与Na(1)O6、Na(2)O8、Na(3)O6和La(1)O9配位多面体连结形成三维网络骨架结构.讨论了Na3La2(BO3)3的晶体结构与倍频效应的关系.     

Extraction of band diagram parameters from Fowler–Nordheim model in silicon dioxide

In electric fields >10⁷ V/cm, we have observed that the conduction current through Si(n⁺)/SiO₂/poly-Si(n⁺) capacitors is larger than that predicted by the classical Fowler–Nordheim law for the case of a triangular potential barrier. This phenomenon appears for both gate polarities just before electric breakdown occurs. An attempt to model this excess current by direct tunneling or by other well-known conduction mechanisms such as Schottky, Poole–Frenkel or hopping effects has been unsuccessful. We have succeeded in interpreting experimental data by considering the SiO₂ layer as a non-triangular potential barrier, which leads to a non-linear relationship between the tunneling length and the applied voltage. By using a semi-linear approach, an oxide conduction band model presenting two potential wells located at approximately from 2.5 nm to within ±0.2 nm from each oxide interface has been obtained. These two singularities may be related to the presence of a non-uniformly distributed positive charge in SiO₂.     

硒代锡酸盐Cd(tren)SnSe3的溶剂热合成与晶体结构

采用溶剂热法合成了一种新的硒代锡酸盐Cd(tren)SnSe3(tren=三(2-氨乙基)胺).单晶X-射线衍射分析表明该化合物为三斜晶系,空间群为P-1,a=0.7752(3)nm,b=0.8128(2)nm,c=1.2467(4)nm,α=97.299(19)°,β=103.639(18)°,γ=107.325(17)°,V=0.7121(4)nm3,Z=2,Dc=2.865 Mg·m-3,Mr=614.21,F(000)=564.该化合物为零维簇状结构,是由[Sn2Se6]单元的反式末端Se原子连接两个[Cd(tren)]2+单元形成的.紫外-可见漫反射光谱研究结果表明,该化合物的禁带宽度为1.80 eV.     

Synthesis and Property of New Blue Emitting Materials with Bulky Side Group

Two emitting compounds, 9,10-bis-[1,1′;3′,1′′]terphenyl-5′-yl-1,5-di-o-tolyl-anthracene [TP-DTA-TP] and 9,10-bis-phenyl[1,1′;3′,1′′]triphenyl-5′-yl-1,5-di-o-tolyl-anthracene [TPB-DTA-TPB] based on new twisted core moiety were synthesized through boration, Suzuki reaction, and Sandmeyer reactions. EL performance was improved by varying the chemical structure of the side group. Physical properties such as optical, electrochemical, and electroluminescent properties were investigated. Synthesized compounds were used as an EML in OLED device: ITO / 2-TNATA (60nm) / NPB (15nm)/ TP-DTA-TP or TPB-DTA-TPB (35 nm) / Alq3 (20nm) / LiF (1nm) / Al (200nm). It was found that TPB-DTA-TPB showed higher luminance efficiency and better C.I.E. value than TP-DTA-TP device.     

Faraday Effect of BSO and BTO Crystals Doped with Cr,Mn and Cu

The influence of both photochromic doping and photochromic transitions on the effect of magneto‐optical rotation (Farady effect ‐ FE) of undoped and doped with Cr, Mn and Cu Bi₁₂SiO₂0 (BSO) and Bi₁₂TiO₂0 (BTO) crystals is studied. The present results show, that Cr, Mn and Cu increase the FE. The influence of Cr, whose affect on the optical activity (OA) of BSO is most significant, here is too negligible (Verdet coefficient (V) increases only with 1‐2 % in the range 700 ‐ 590 nm). The Mn‐doping of BSO led to a V‐increase with about of 11 % in the range 400 ‐ 700 nm, as at 460 nm the relative increase of V reaches to about 30 %. The influence of Cu on FE in BSO (likely the case of the natural optical rotation) is again significant. Thus, the influence of V in the case of BSO:Cu is about 18 % in the range 700 ‐ 480 nm as reaches 28 % in the shortwave region at 480 nm. However, in BTO:Cu (0.02 mol.% Cu) the influence of Cu is opposite in respect of both effects. Now the values of V increase with 21 % at 630 nm, 22 % at 590 nm, 42 % at 520 nm, and 73 % at 480 nm in comparison to BTO‐undoped.