摘要:

Ba‐Cu oxides with certain compositions were found to be meltable or partly meltable at a relatively low temperature of 950 °C. High‐quality, dense, and void‐free high‐temperature superconductors based on rare earth(RE)‐Ba‐Cu oxides of the form REBa2Cu3O6.5+xhave been made by reactions between molten Ba‐Cu oxides and solid RE‐containing materials at the same temperature. This has allowed superconductive components to be made in a wide variety of shapes. This melt process will significantly alter oxide superconductor preparation procedures, and will allow growth of large single crystals aiding in the understanding of the mechanism of superconductivity and in the search for superconductivity at even higher transition temperatures.

ISSN:0003-6951    

DOI:10.1063/1.98492

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The spatial variation of the oxide field in metal‐oxide‐silicon devices due to charge trapping under electron injection stress is included in a self‐consistent trapping model. The model predicts the spatial distribution of the stress‐generated trapping sites and their occupation level under different conditions of applied voltages and total injected charge. The calculated results agree quite well with the experimental results of prolonged charge injection, as expressed in shifts of the flatband voltage.

ISSN:0003-6951    

DOI:10.1063/1.98493

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Applications involving the semiconductor‐electrolyte interface require a good understanding of charge carrier transport at the interface and the related concept of Fermi level in an electrolyte. The meaning of electrolyte Fermi level is currently an active research question. As an experimental approach to the problem, we have developed a convenient technique, using a Kelvin probe. Using this, we can measure the surface potential without making contact to the solution. An important question is how the surface potential is related to the solution composition. We find that surface potential depends on thepH of the solution in a well‐defined way. From our data, we can estimate the absolute emf of the hydrogen electrode. The result agrees well with published values, determined by other means.

ISSN:0003-6951    

DOI:10.1063/1.98494

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The conversion from fast to slow positrons by several thin (0.3–7 &mgr;m) film moderators has been studied. Positrons from a radioactive22Na source enter the film where some are thermalized, consequently diffuse to the surface opposite to the source and are emitted with low energies (1–4 eV). The experimental data show that the conversion efficiency to slow positrons ranges from 1×10−4to 9.1×10−4for good moderators. The moderator efficiency was found to be very sensitive to annealing temperatures.

ISSN:0003-6951    

DOI:10.1063/1.98495

出版商:AIP    

年代:1987

数据来源: AIP