Abstract
Some applications of high-temperature superconductors where their radiative behavior is important, such as bolometers, optically triggered switches and gates, and space-cooled electronics, require the superconductor to be in the form of a very thin film whose radiative properties cannot be adequately represented by a semi-infinite analysis. Two properties of particular importance are the film absorptance and the combined film/substrate absorptance, which are crucial to the operation of many devices. Here, calculations of the spectral, normal-incidence absorptance of superconducting- state Y-Ba-Cu-O films on MgO substrates suggest that a decrease in the film thickness often leads to an increase in both the film and the film/substrate absorptance. Furthermore, both can exhibit a maximum at some optimal value of film thickness. Room-temperature experiments verify the qualitative features of the spectral film/substrate absorptance, indicating the assumption that the film is a smooth, continuous slab with a refractive index equal to that of well-aligned bulk Y-Ba-Cu-O is valid, at least in the normal state and for films as thin as 35 nm.
Original language | English (US) |
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Pages (from-to) | 227-233 |
Number of pages | 7 |
Journal | Journal of Heat Transfer |
Volume | 114 |
Issue number | 1 |
DOIs | |
State | Published - Feb 1992 |
Externally published | Yes |
Keywords
- Cryogenics
- Radiation
ASJC Scopus subject areas
- General Materials Science
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering