ISSN:
1572-9605
Keywords:
Tl-Ba-Ca Cu-O superconductors
;
HTSC/ferroelectric tunable microwave devices
;
HTSC/ferroelectric multilayer structures
Source:
Springer Online Journal Archives 1860-2000
Topics:
Electrical Engineering, Measurement and Control Technology
,
Physics
Notes:
Abstract We describe materials deposition and characterization for a broad class of tunable microwave devices using high-temperature oxide superconductor and voltage-tunable oxide ferroelectric thin-film multilayer structures. Tl-Ba-Ca-Cu-O thin films deposited by sputtering ore-beam evaporation were patterned into microwave resonators, each consisting of two colinear microstrip line sections separated by a 5–20μm gap. A Ba0.1Sr0.9TiO3 (BST) layer was then over-coated to fill the gap. The relative dielectric constant of the BST films deposited by physical vapor or chemical techniques was measured at 77 K in the 1–10 MHz range and found to vary by up to a factor of 2 or more with voltage bias in test capacitor structures using Pt electrodes. In the BST (variable capacitor)-HTSC microwave resonator structures, the change of the relative dielectric constant of the BST under voltage bias has allowed variation of the fundamental frequency of up to 80 MHz in the 5–10 GHz range at 4 K. Film deposition by various techniques and associated structural, morphological, and electronic properties, as well as materials compatibility issues, are discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00724590
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