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

29 Feb 1988

Volume 52, Issue 9, pp. 679-761

Page 2 of 2 Pages Previous Page | Jump to Page

Equilibrium of a magnet floating above a superconducting disk

Richard Williams and J. R. Matey

Appl. Phys. Lett. 52, 751 (1988); http://dx.doi.org/10.1063/1.99336 (3 pages) | Cited 20 times

Full Text: | Download PDF

Show Abstract
A superconducting body will repel a nearby magnet. The repulsion is due to the perfect diamagnetism resulting from the Meissner effect. A small magnet will float above a superconducting disk at an equilibrium position over the disk center, stable against lateral displacements. It is not intuitively obvious why the potential energy of the magnet over a flat disk should have a minimum at the center, rather than a maximum. We have measured the properties of the attractive potential well of a YBa2Cu3O7 disk by two experiments. In the first, we use a low‐frequency magnetic field, 0–100 Hz, to excite oscillations of a small, freely levitating bar magnet about its equilibrium position. We find sharp resonances, corresponding to longitudinal, transverse, and torsional modes of oscillation. The frequencies of these resonances define the properties near the bottom of the potential well. In the second experiment, we attach the magnet to a vertical glass fiber of known stiffness. The magnet is suspended horizontally a small known distance, z, above the superconducting disk. By moving the magnet from the center of the disk to the edge and measuring the bending of the support fiber as a function of position we determine the shape of the potential curve for large displacements and the total energy needed to escape from the well.
Show PACS
74.25.Ha Magnetic properties including vortex structures and related phenomena
74.70.-b Superconducting materials other than cuprates
84.71.Ba Superconducting magnets; magnetic levitation devices

Low‐temperature preparation of high Tc superconducting thin films

X. D. Wu, A. Inam, T. Venkatesan, C. C. Chang, E. W. Chase, P. Barboux, J. M. Tarascon, and B. Wilkens

Appl. Phys. Lett. 52, 754 (1988); http://dx.doi.org/10.1063/1.99337 (3 pages) | Cited 125 times

Full Text: | Download PDF

Show Abstract
Thin superconducting films of Y‐Ba‐Cu‐O were prepared at 650 °C using the pulsed laser deposition technique. The as‐deposited films were fully superconducting at low temperature (30 K). After annealing in oxygen at 450 °C for 3 h, the films exhibited superconductivity with zero resistance at temperatures as high as 83 K. Film‐substrate interface reaction was minimal as revealed by Rutherford backscattering and Auger electron spectrometry. These films processed at such low temperatures are also found to have excellent planar surface morphology and high critical current density.
Show PACS
74.78.-w Superconducting films and low-dimensional structures
74.70.-b Superconducting materials other than cuprates
81.40.Rs Electrical and magnetic properties related to treatment conditions
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy

Resonance absorption of radiation field by an intense relativistic electron beam in inverse cyclotron maser geometry

Sunao Kawasaki, Kei‐ichi Kamada, Masaru Masuzaki, and Hiroshi Takuma

Appl. Phys. Lett. 52, 757 (1988); http://dx.doi.org/10.1063/1.99338 (3 pages)

Full Text: | Download PDF

Show Abstract
Attenuation of the radiation field by an intense, mildly relativistic electron beam moving in a longitudinal magnetic field was studied experimentally in the frequency range of x‐band microwaves. Nearly complete absorption of the radiation externally injected along the beam was found to be near a particular value of the axial guide magnetic field. The interaction mechanism is identified as the coupling between the waveguide modes and the beam cyclotron wave propagating backwards. It is concluded that the absorption should be the inverse process of the electron cyclotron maser by a dense relativistic electron beam.
Show PACS
84.40.Ik Masers; gyrotrons (cyclotron-resonance masers)
41.75.Ht Relativistic electron and positron beams
FREE

Comment on ‘‘Pair of local vibration mode absorption bands related to EL2 defects in semi‐insulating GaAs’’ [Appl. Phys. Lett. 50, 1666 (1987)]

U. V. Desnica, M. Skowronski, and M. C. Cretella

Appl. Phys. Lett. 52, 760 (1988); http://dx.doi.org/10.1063/1.99339 (1 page) | Cited 2 times

Full Text: | Download PDF

Abstract Unavailable
Show PACS
63.20.Pw Localized modes
78.30.-j Infrared and Raman spectra
78.40.Fy Semiconductors
71.55.Eq III-V semiconductors
78.30.Fs III-V and II-VI semiconductors
FREE

Response to ‘‘Comment on ‘Pair of local vibration mode absorption bands related to EL2 defects in semi‐insulating GaAs’ ’’ [Appl. Phys. Lett. 52, 760 (1988)]

Chunying Song, Weikun Ge, Desheng Jiang, and Chenchia Hsu

Appl. Phys. Lett. 52, 761 (1988); http://dx.doi.org/10.1063/1.99340 (1 page)

Full Text: | Download PDF

Abstract Unavailable
Show PACS
78.30.-j Infrared and Raman spectra
78.40.Fy Semiconductors
71.55.Eq III-V semiconductors
78.30.Fs III-V and II-VI semiconductors
63.20.Pw Localized modes
Page 2 of 2 Pages Previous Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close