摘要:

Superconducting films of Bi2Sr2CaCu2Oxhave been fabricated on single‐crystal MgO substrates by a low‐temperatureinsituprocess. Using a substrate temperatureTs≊645 °C, metallic films with a superconducting onset of 90–100 K and an extrapolatedTc0=56 K have been obtained. X‐ray diffraction shows the films to bec‐axis oriented. Electron microscopy reveals that the films are not significantly smoother than films which were post‐annealed at 865 °C, and that some segregation into nonsuperconducting phases had occurred. The exact mechanism by which crystallization and superconductivity occurs at such low temperatures is not yet known, but it can be speculated that the surface atoms are less constrained and thus have a smaller energy barrier to overcome in forming a crystal structure.

ISSN:0003-6951    

DOI:10.1063/1.102347

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

An optical pyrometer has been used to measure apparent temperature oscillations during the growth of GaAs/GaAlAs heterostructures by molecular beam epitaxy. The oscillations are due to an optical interference effect in the epitaxial layers and the period can be related to both growth rate and alloy composition. Measurements can be carried out on rotating substrates throughout the deposition cycle of complex device structures, and provide a convenient means of monitoring the uniformity of the deposition process.

ISSN:0003-6951    

DOI:10.1063/1.102082

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Persistent image storage has been successfully performed in organopolysilane‐based xerographic photoreceptors by ultraviolet image exposure, which converts organopolysilane into intrinsically insulating material with no charge carrier transporting ability due to photodecomposition. The stored image can be read out repeatedly as a negative toner image by the usual xerographic process with uniform visible light illumination, suggesting an application of the present photoreceptor to the xerographic printing master.

ISSN:0003-6951    

DOI:10.1063/1.102083

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Highest precision mass spectroscopy and other highly accurate measurements have been carried out in Penning traps with metal electrodes painstakingly shaped along hyperbolic contours. A single electron has now been observed in a much simpler, cylindrical trap with equally good signal‐to‐noise ratio, thus demonstrating the possibility of conducting such experiments in a more readily constructed apparatus and opening the possibility of some new experiments. An essential requirement is the careful choice of electrode lengths to make the size of the electric quadrupole potential insensitive to adjustments which minimize deviations from an electric quadrupole.

ISSN:0003-6951    

DOI:10.1063/1.102084

出版商:AIP    

年代:1989

数据来源: AIP

ISSN:0003-6951    

DOI:10.1063/1.102086

出版商:AIP    

年代:1989

数据来源: AIP