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91.
M. Geddo R. Ferrini G. Guizzetti M. Patrini S. Franchi P. Frigeri G. Salviati L. Lazzarini 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,16(1):19-24
We report on a photoreflectance investigation in the 0.8-1.5 eV photon energy range and at temperatures from 80 to 300 K on
stacked layers of InAs/GaAs self-assembled quantum dots (QDs) grown by Atomic-Layer Molecular Beam Epitaxy. We observed clear
and well-resolved structures, which we attribute to the optical response of different QD families. The dependence of the ground
state transition energy on the number of stacked QD layers is investigated and discussed considering vertical coupling between
dots of the same column. It is shown that Coulomb interaction can account for the observed optical response of QD families
with different morphology coexisting in the same sample.
Received 17 November 1999 相似文献
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We perform MD simulations of the nanoindentation on (001) and (111) surfaces of Ag–Ni multilayers with different modulation periods, and find that both the hardness and maximum force increase with the increase of modulation period, in agreement with the inverse Hall–Petch relation. A prismatic partial dislocation loop is observed in the Ni(111)/Ag(111) sample when the modulation period is relatively large. We also find that misfit dislocation network shows a square shape for the Ni(111)/Ag(111) interface, while a triangle shape for the Ni(001)/Ag(001) interface. The pyramidal defect zones are also observed in Ni(001)/Ag(001) sample, while the intersecting stacking faults are observed in Ni(111)/Ag(111) sample after dislocation traversing interface. The results offer insights into the nanoindentation behaviors in metallic multilayers, which should be important for clarifying strengthening mechanism in many other multilayers. 相似文献
95.
Yueyue Liu Xiangqian Wang Hongkang Xie Hongmei Feng Xiaolei Li Huiliang Wu Zengtai Zhu Yi Huang Wenshu Liu Genliang Han Jianbo Wang Qingfang Liu 《Physics letters. A》2019,383(34):125986
The effect of bilayer repeats (N) on the static and dynamic magnetic properties of Co/Ni multilayers was investigated. The effective perpendicular magnetic anisotropy constant of multilayers drops from erg/cm3 to erg/cm3 with N increasing from 5 to 11. For Co/Ni multilayers with , sharp magnetization switching was observed. In contrast, Co/Ni multilayers with have a long tail in the hysteresis loop. Ferromagnetic resonance measurements show that intrinsic Gilbert damping changes from 0.021 to 0.016 with increase in N and is inversely proportional to N. This study provides a deep understanding and effective control of magnetic properties of Co/Ni multilayers for spintronics devices. 相似文献
96.
Zheng-Chuan Wang Qing-Rong Zheng Gang Su Bao-Heng Zhao 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,19(4):589-597
In this paper, we apply Büttiker's gauge invariant, charge conservation, nonlinear transport theory to explore the spin-polarized
tunneling of ferromagnet/insulator (semiconductor) single and double junctions. The Green function of spin-polarized tunneling
is calculated by the tight-binding approximation method. The energy and the angle (between the molecular field and the vertical
axis) dependences of the weakly nonlinear dc transport coefficient and the linear low frequency ac transport coefficient are
investigated. The ac tunneling magnetoresistance is also discussed.
Received 1st September 2000 and Received in final form 5 December 2000 相似文献
97.
V.I.T.A. de Rooij-Lohmann A.E. YakshinE. Zoethout J. VerhoevenF. Bijkerk 《Applied Surface Science》2011,257(14):6251-6255
Thin interlayers are essential for high-quality multilayer optics. We present the first investigation of reducing the interlayer thickness of Mo/Si multilayer structures by cooling the substrate with liquid nitrogen during the deposition. The structures were deposited by means of electron beam evaporation. Even after warming up to room temperature prior to analysis, the interlayers that formed upon cryogenic deposition were found to be approximately 60% thinner compared to room temperature deposition. The interlayer thickness reduction at low temperature and its preservation upon warming up are attributed to a lower mobility of adatoms, reduced surface segregation of Si during Mo-on-Si growth, and/or crystallization of Mo. 相似文献
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Silica sol-gel single layer AR coatings are used in high peak power pulsed lasers due to their high laser induced damage threshold (LIDT) and their low refractive index (1.22). We have used sol-gel processing to spin and dip coat multilayers of alternating high index (zirconia/hafnia) and low index (base catalysed silica) sol-gels on to fused silica substrates. When tailored at the correct thickness these stacks have shown >95% reflectivity at 355 nm and normal incidence whilst retaining a high LIDT. Depth profiling using Dynamic Secondary Ion Mass Spectrometry (DSIMS) and Rutherford back scattering (RBS) through these multilayer coatings has revealed the effect of increasing the number of layers in the stack. Results are presented for both spin and dip coated multilayers and a significant difference in the interfacial boundary is seen between the two coating processes. These differences are related to changes in the LIDT of the coatings. Individual layer thicknesses were estimated using this technique and compared to values gained from UV-Visible spectroscopy. TEM analysis of an ion-milled cross-section of the multilayers was performed showing the colloidal silica coatings and the depth of interpenetration of the interfaces. 相似文献
100.