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The effect of interface roughness on the perpendicular exchange bias of NiO/CoPt/Pt stacking structure

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Science China(Technological Sciences) 2021年第3期64卷 605-610页

作者： GAO Ying HARUMOTO Takashi NAKAMURA Yoshio SHI Ji Department of Materials Science and Engineering Tokyo Institute of Technology2-12-1OokayamaMeguro-kuTokyo 152-8550Japan

An orthogonal coupling structure of NiO/CoPt/Pt/glass with perpendicular exchange bias effect has been *** exchange bias is found to be strongly dependent on the interface roughness between NiO and CoPt *** conventional inverse proportionality of the exchange bias field with the ferromagnetic thickness is not applicable to this top-pinned stacking ***,an anomalous ferromagnetic thickness dependence of blocking temperature is also observed.A simulation on the basis of a spin configuration model with defects at the interface agrees well with the experimental *** findings suggest considerable contribution of the interface roughness to the perpendicular exchange bias.

关键词： perpendicular exchange bias interface roughness FM thickness blocking temperature

Effects of interface roughness on photoluminescence full width at half maximum in GaN/AlGaN quantum wells

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Chinese Physics B 2014年第11期23卷 562-565页

作者：王维颖刘贵鹏金鹏毛德丰李维王占国田武陈长清 Key Laboratory of Semiconductor Materials Science and Beijing Key Laboratory of Low-dimensional Semiconductor Materials and Devices Institute of Semiconductors Chinese Academy of Sciences Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology

Low temperature photoluminescence （PL） measurements have been performed for a set of GaN/AlxGal xN quantum wells （QWs）. The experimental results show that the optical full width at half maximum （FWHM） increases relatively rapidly with increasing A1 composition in the AlxGal xN barrier, and increases only slightly with increasing GaN well width. A model considering the interface roughness is used to interpret the experimental results. In the model, the FWHM＇s broadening caused by the interface roughness is calculated based on the triangle potential well approximation. We find that the calculated results accord with the experimental results well.

关键词： GaN/A1GaN quantum wells interface roughness optical full width at half maximum

Compression failure conditions of concrete-granite combined body with different roughness interface

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International Journal of Mining Science and Technology 2023年第3期33卷 297-307页

作者： Huan Gao Yue Zhai Tienan Wang Yubai Li Fandong Meng Houquan Zhang Yan Li School of Geology Engineering and Geomatics Chang’an UniversityXi’an 710064China Key Laboratory of Western China’s Mineral Resources and Geological Engineering of Ministry of Education Chang’an UniversityXi’an 710054China State Key Laboratory of Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China

Bedrock and concrete lining are typical composite structures in the engineering field and the stability of the geological body and engineering body is directly connected to the mechanical properties of the composite *** this background,the study provides the transverse isotropic equivalent model of concrete-granite double-layer composite based on the notion of strain energy *** that the strength failure of concrete and granite meets the Mohr-Coulomb criterion,then the strength failure model of the combined body considering the joint roughness coefficient(JRC)is derived,and the influences of JRC,the height ratio of concrete to granite,and confining pressure on the strength failure characteristics of the combined body are emphatically ***,the model applicability is illustrated by the uniaxial and triaxial compression tests on concrete monomer,granite monomer and concretegranite composite samples(CGCSs)with different *** results revealed that the compressive strength of the composite is closer to the concrete with lower strength in the combined body under different confining *** interface roughness causes to raise the compressive strength of the composite due to interfacial adhesion between concrete and granite,and a slowing growth trend is observed in compressive strength as *** model can provide a certain reference for the stability design and evaluation of engineering rock mass.

关键词： Concrete-granite combined body Compression failure condition interface roughness Mechanical model

Optimization of mechanical and safety properties by designing interface characteristics within energetic composites

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Defence Technology（防务技术） 2024年第12期42卷 59-72页

作者： Guijun Wang Yanqing Wu Kun Yang Quanzhi Xia Fenglei Huang State Key Laboratory of Explosion Science and Safety Protection Beijing Institute of TechnologyBeijing 100081China

The interfacial structure has an important effect on the mechanical properties and safety of the energetic *** this work,a mesostructure model reflecting the real internal structure of PBX is established through image digital modeling and vectorization processing *** microscopic molecular structure model of PBX is constructed by molecular dynamics,and the interface bonding energy is calculated and transferred to the mesostructure *** simulations are used to study the influence of the interface roughness on the dynamic compression and impact ignition response of PBX,and to regulate and optimize the mechanical properties and safety of the explosive to obtain the optimal design of the surface roughness of the explosive *** results show that the critical hot spot density of PBX ignition under impact loading is 0.68 mm^(-2).The improvement of crystal surface roughness can improve the mechanical properties of materials,but at the same time it can improve the impact ignition sensitivity and reduce the safety of *** optimal friction coefficient range for the crystal surface that satisfies both the mechanical properties and safety of PBX is *** work can provide a reference basis for the formulation design and production processing of energetic materials.

关键词： Polymer-bonded explosives interface roughness Mechanical properties Hot spot Mesostructure optimization

Numerical Study on Effect of Non-uniform CMAS Penetration on TGO Growth and interface Stress Behavior of APS TBCs

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Chinese Journal of Mechanical Engineering 2021年第6期34卷 98-113页

作者： Zhenwei Cai Zifan Zhang Yingzheng Liu Xiaofeng Zhao Weizhe Wang Key Laboratory of Power Machinery and Engineering School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai200240China Gas Turbine Research Institute Shanghai Jiao Tong UniversityShanghai200240China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai200240China

The penetration of CaO-MgO-Al_(2)O_(3)-SiO_(2)(CMAS)is one of the most significant factors that induce the failure of air-plasma-sprayed thermal barrier coatings(APS TBCs).The direct penetration of CMAS changes the thermal/mechanical properties of the top coat(TC)layer,which affects the thermal mismatch stress behavior and the growth of thermally grown oxide(TGO)at the TC/bond coat(BC)interface,thereby resulting in a more complicated interface stress *** the present study,a two-dimensional global model of APS TBCs with half of the TC layer penetrated by CMAS is established to investigate the effect of non-uniform CMAS penetration on the interface stress ***,a local model extracted from the global model is established to investigate the effects of interface morphologies and CMAS penetration *** results show that non-uniform CMAS penetration causes non-uniform TGO growth in APS TBCs,which consequently causes the stress behavior to vary along the ***,the CMAS pen-etration depth imposes a significant effect on the TC/TGO interface stress behavior,whereas the interface roughness exerts a prominent effect on the stress level at the BC/TGO interface under CMAS *** study reveals the mechanism associated with the effect of non-uniform CMAS penetration on the interface stress behavior in APS TBCSs.

关键词： CMAS non-uniform penetration TGO growth interface stress CMAS penetration depth interface roughness

The low-temperature mobility of two-dimensional electron gas in AlGaN/GaN heterostructures

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Chinese Physics B 2008年第7期17卷 2689-2695页

作者：张金风毛维张进城郝跃 Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices Microelectronics InstituteXidian University

To reveal the internal physics of the low-temperature mobility of two-dimensional electron gas （2DEG） in Al- GaN/GaN heterostructures, we present a theoretical study of the strong dependence of 2DEG mobility on Al content and thickness of AlGaN barrier layer. The theoretical results are compared with one of the highest measured of 2DEG mobility reported for AlGaN/GaN heterostructures. The 2DEG mobility is modelled as a combined effect of the scat- tering mechanisms including acoustic deformation-potential, piezoelectric, ionized background donor, surface donor, dislocation, alloy disorder and interface roughness scattering. The analyses of the individual scattering processes show that the dominant scattering mechanisms are the alloy disorder scattering and the interface roughness scattering at low temperatures. The variation of 2DEG mobility with the barrier layer parameters results mainly from the change of 2DEG density and distribution. It is suggested that in AlGaN/GaN samples with a high Al content or a thick AlGaN layer, the interface roughness scattering may restrict the 2DEG mobility significantly, for the AlGaN/GaN interface roughness increases due to the stress accumulation in AlGaN layer.

关键词： two-dimensional electron gas mobility AlGaN/GaN heterostructures interface roughness

Microstructural stability of NiO-containing spin valves annealed at room temperature

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Chinese Physics C 2009年第11期33卷 944-948页

作者：张爱梅蔡宏灵翟章印杜军吴小山贾全杰 College of Science Hohai University Lab of Solid State Microstructures Department of Physics Nanjing University BSRF Institute of High Energy Physics CAS

Microstructure of NiO-containing Co/Cu/Co spin valves （CCC-SV） annealed at room temperature for nearly four years has been studied by synchrotron radiation X-ray diffraction. With the annealing time expanding, the thickness of each sub-layer remains nearly unchanged while the interface roughness varies obviously compared with that of samples without annealing. The roughness at the interface of NiO/Co decreases with the annealing time increasing for both of the samples with NiO layer on the top （TSV） and under the bottom （BSV） of CCC-SV. On the other hand, the roughness at Co/Cu interface increases with the annealing time expanding for BSV while it decreases for TSV. These results indicate that the structure of TSV is more stable than that of BSV.

关键词： interface roughness X-ray reflectivity spin valves

Reduction of insertion loss after annealing of silicon oxynitride optical waveguides

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Chinese Physics B 2002年第1期11卷 83-86页

作者：贺德衍 K.A.McGreer DepartmentofPhysics LanzhouUniversityLanzhou730000China DepartmentofPhysics UniversityofManitobaWinnipegMBR3T2N2Canada

The insertion losses of silicon oxynitride (SiON) waveguides have been measured in the 1550 nm wavelength *** waveguide structure consisted of a 2.0μm SiON waveguide core with a refractive index of 1.50, a 0.5μm SiO2 uppercladding and a 5.0μm SiO2 lower cladding with a refractive index of 1.45. It was found that the wavelength-dependentinsertion losses of the waveguide were greatly reduced by annealing, and the loss was decreased more than 5.7 dB/cm at1550 nm after annealing at optimum conditions. The former was attributed to the reduction of the absorption caused by N-H and Si-H vibration modes, and the latter was due to the improvement of the interface roughness and homogeneity in the waveguides after annealing.

关键词： SiON optical waveguide insertion loss annealing interface roughness

High powerλ~8.5μm quantum cascade laser grown by MOCVD operating continuous-wave up to 408 K

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Journal of Semiconductors 2021年第11期42卷 55-60页

作者： Teng Fei Shenqiang Zhai Jinchuan Zhang Ning Zhuo Junqi Liu Lijun Wang Shuman Liu Zhiwei Jia Kun Li Yongqiang Sun Kai Guo Fengqi Liu Zhanguo Wang Key Laboratory of Semiconductor Materials Science Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices Beijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

Robust quantum cascade laser(QCL)enduring high temperature continuous-wave(CW)operation is of critical importance for some *** report on the realization of lattice-matched InGaAs/InAlAs/InP QCL materials grown by metal-organic chemical vapor deposition(MOCVD).High interface quality structures designed for light emission at 8.5μm are achieved by optimizing and precise controlling of growth conditions.A CW output power of 1.04 W at 288 K was obtained from a 4 mm-long and 10μm-wide coated *** maximum wall-plug efficiency and threshold current density were 7.1%and 1.18 kA/cm2,*** device can operate in CW mode up to 408 K with an output power of 160 mW.

关键词： quantum cascade laser metal-organic chemical vapor deposition continuous-wave interface roughness