APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

13 Nov 1989

Volume 55, Issue 20, pp. 2045-2148

Page 2 of 2 Pages Previous Page | Jump to Page

Molecular beam epitaxy of superconducting (Rb,Ba)BiO3

E. S. Hellman, E. H. Hartford, and R. M. Fleming

Appl. Phys. Lett. 55, 2120 (1989); http://dx.doi.org/10.1063/1.102343 (3 pages) | Cited 17 times

Full Text: | Download PDF

Show Abstract
The simple cubic perovskite (Rb,Ba)BiO3 can be grown at temperatures below 350 °C by molecular beam epitaxy using a rf plasma atomic oxygen source. Films with superconducting onsets in resistivity as high as 27 K are obtained without annealing. The epitaxy proceeds in the normal (100) orientation on {100} SrTiO3, despite a 10% lattice mismatch. (110) epitaxy and spotty reflection high‐energy electron diffraction (RHEED) patterns are obtained on {100} MgO substrates, despite the good lattice match for (100) growth. Streaked and spotty RHEED patterns have been obtained on either substrate. Sticking coefficients for bismuth depend on the growth conditions, indicating that the epitaxy is partially controlled by desorption kinetics.
Show PACS
74.70.-b Superconducting materials other than cuprates
74.78.-w Superconducting films and low-dimensional structures
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy

Superconducting (Bi,Pb)‐Ca‐Sr‐Cu‐O thin films prepared in situ by laser ablation

Z. Ivanov and G. Brorsson

Appl. Phys. Lett. 55, 2123 (1989); http://dx.doi.org/10.1063/1.102344 (3 pages) | Cited 14 times

Full Text: | Download PDF

Show Abstract
Superconducting Bi‐Ca‐Sr‐Cu‐O and Bi‐Pb‐Ca‐Sr‐Cu‐O films were grown in situ by excimer laser ablation from pressed powder and sintered superconducting targets, respectively. The substrate temperature during deposition was found to be important to obtain a maximum transition temperature. Both 110 and 80 K superconducting phases were obtained in films with a zero resistance at 74 K.
Show PACS
74.70.-b Superconducting materials other than cuprates
74.78.-w Superconducting films and low-dimensional structures
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
79.20.Ds Laser-beam impact phenomena

Surface segregation of Ba in polycrystalline YBa2Cu3O7 oxides: The effect of silver

A. G. Schrott, G. Singco, and K. N. Tu

Appl. Phys. Lett. 55, 2126 (1989); http://dx.doi.org/10.1063/1.102081 (3 pages) | Cited 6 times

Full Text: | Download PDF

Show Abstract
We have investigated the effect of annealing polycrystalline YBa2Cu3O7−δ samples in a He ambient and in vacuum, on the composition of their internal surfaces. X‐ray photoelectron spectroscopy (XPS) data indicate a decrease in the amount of BaCO3 but a higher proportion of Ba at the near‐surface region upon low‐temperature annealing in He or vacuum. The latter effect seems to derive from the presence of a surface barrier for oxygen outdiffusion, and can be prevented by diffusing Ag into the polycrystalline sample. Changes in the cutoff energies of the ultraviolet photoelectron spectra indicate that a submonolayer coverage of Ag is sufficient to produce a change in the work function of 0.3 eV, corresponding to the lowering of the surface barrier.
Show PACS
74.70.-b Superconducting materials other than cuprates
81.40.Rs Electrical and magnetic properties related to treatment conditions
66.30.Lw Diffusion of other defects
73.30.+y Surface double layers, Schottky barriers, and work functions

Scanning tunneling microscopy investigations of the local structure of Tl2Ba2CaCu2O8 single crystals

X. L. Wu, C. M. Lieber, D. S. Ginley, and R. J. Baughman

Appl. Phys. Lett. 55, 2129 (1989); http://dx.doi.org/10.1063/1.102345 (3 pages) | Cited 16 times

Full Text: | Download PDF

Show Abstract
The in‐plane structure of single‐crystal samples of Tl2Ba2CaCu2O8 has been imaged at room temperature using a scanning tunneling microscope. Atomic‐resolution surface images exhibit areas in which the structure has tetragonal symmetry (peak spacing 2.5±0.2 Å) and regions in which the structure is distorted from tetragonal symmetry. The lattice spacing indicates that the observed structure corresponds to the in‐plane thallium and oxygen positions. The observation of both sites also suggests that the Tl‐O band makes a significant contribution to the density of states near the Fermi level. In addition, a weak one‐dimensional superlattice (period 10±0.5 Å) which shows short‐range order has been observed.
Show PACS
74.70.-b Superconducting materials other than cuprates
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
68.35.B- Structure of clean surfaces (and surface reconstruction)

Spatial imaging of the critical current density in epitaxial Y1Ba2Cu3O7 films

R. Gross, K. Hipler, J. Mannhart, R. P. Huebener, P. Chaudhari, D. Dimos, C. C. Tsuei, J. Schubert, and U. Poppe

Appl. Phys. Lett. 55, 2132 (1989); http://dx.doi.org/10.1063/1.102346 (3 pages) | Cited 10 times

Full Text: | Download PDF

Show Abstract
We report the first spatially resolved measurement of the critical transport current density of c‐axis oriented epitaxial Y1Ba2Cu3O7 films on 〈100〉 SrTiO3 using low‐temperature scanning electron microscopy (LTSEM). The local critical current density, imaged with a spatial resolution of ∼1 μm, has been found to vary considerably in these films. Possible reasons for the observed spatial inhomogeneities are surface imperfections of the substrate and precipitates in the film. The spatial inhomogeneity of the critical current density in epitaxial films might be a reason for differences in the temperature dependences of the critical current density obtained by magnetic and transport measurements.
Show PACS
74.78.-w Superconducting films and low-dimensional structures
74.70.-b Superconducting materials other than cuprates
74.25.Uv Vortex phases (includes vortex lattices, vortex liquids, and vortex glasses)

Properties of sputtered superconducting films of Bi2Sr2CaCu2Ox made by low‐temperature in situ growth

R. T. Kampwirth, P. H. Andersen, D. B. McDonald, D. J. Miller, K. E. Gray, Z. F. Sungaila, U. Balachandran, and A. Wagner

Appl. Phys. Lett. 55, 2135 (1989); http://dx.doi.org/10.1063/1.102347 (3 pages) | Cited 10 times

Full Text: | Download PDF

Show Abstract
Superconducting films of Bi2Sr2CaCu2Ox have been fabricated on single‐crystal MgO substrates by a low‐temperature in situ process. Using a substrate temperature Ts≊645 °C, metallic films with a superconducting onset of 90–100 K and an extrapolated Tc0=56 K have been obtained. X‐ray diffraction shows the films to be c‐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.
Show PACS
74.70.-b Superconducting materials other than cuprates
74.78.-w Superconducting films and low-dimensional structures
68.55.-a Thin film structure and morphology
74.20.Mn Nonconventional mechanisms
74.20.Rp Pairing symmetries (other than s-wave)

In situ growth rate measurements during molecular beam epitaxy using an optical pyrometer

A. J. SpringThorpe, T. P. Humphreys, A. Majeed, and W. T. Moore

Appl. Phys. Lett. 55, 2138 (1989); http://dx.doi.org/10.1063/1.102082 (3 pages) | Cited 26 times

Full Text: | Download PDF

Show Abstract
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.
Show PACS
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
07.20.Ka High-temperature instrumentation; pyrometers
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
68.55.Nq Composition and phase identification

New‐type xerographic multiduplication using organopolysilane‐based memory photoreceptor drawn by ultraviolet image exposure

Kenji Yokoyama and Masaaki Yokoyama

Appl. Phys. Lett. 55, 2141 (1989); http://dx.doi.org/10.1063/1.102083 (3 pages) | Cited 14 times

Full Text: | Download PDF

Show Abstract
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.
Show PACS
85.60.-q Optoelectronic devices
73.50.Pz Photoconduction and photovoltaic effects
42.79.Vb Optical storage systems, optical disks
78.66.Qn Polymers; organic compounds

One electron in an orthogonalized cylindrical Penning trap

Joseph Tan and Gerald Gabrielse

Appl. Phys. Lett. 55, 2144 (1989); http://dx.doi.org/10.1063/1.102084 (3 pages) | Cited 19 times

Full Text: | Download PDF

Show Abstract
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.
Show PACS
41.75.Fr Electron and positron beams
41.20.Cv Electrostatics; Poisson and Laplace equations, boundary-value problems
41.20.Gz Magnetostatics; magnetic shielding, magnetic induction, boundary-value problems
FREE

Comment on ‘‘Investigation of the critical layer thickness in elastically strained InGaAs/GaAlAs quantum wells by photoluminescence and transmission electron microscopy’’ [Appl. Phys. Lett. 54, 48 (1989)]

J. Woodhead

Appl. Phys. Lett. 55, 2147 (1989); http://dx.doi.org/10.1063/1.102085 (1 page) | Cited 1 time

Full Text: | Download PDF

Abstract Unavailable
Show PACS
78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors
78.66.Hf II-VI semiconductors
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.55.-a Thin film structure and morphology
FREE

Response to ‘‘Comment on ‘Investigation of the critical layer thickness in elastically strained InGaAs/GaAlAs quantum wells by photoluminescence and transmission electron miscroscopy’ ’’ [Appl. Phys. Lett. 55, 2147 (1989)]

J.‐P. Reithmaier, H. Cerva, and R. Lösch

Appl. Phys. Lett. 55, 2147 (1989); http://dx.doi.org/10.1063/1.102086 (2 pages)

Full Text: | Download PDF

Abstract Unavailable
Show PACS
78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors
78.66.Hf II-VI semiconductors
68.55.-a Thin film structure and morphology
68.35.B- Structure of clean surfaces (and surface reconstruction)
Page 2 of 2 Pages Previous Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close