Digitale Medien
[S.l.]
:
American Institute of Physics (AIP)
Journal of Applied Physics
78 (1995), S. 4591-4595
ISSN:
1089-7550
Quelle:
AIP Digital Archive
Thema:
Physik
Notizen:
Epitaxial trilayer heterostructures of YBa2Cu3O7−δ/BaxSr1−xTiO3/YBa2Cu3O7−δ were grown on silicon-on-sapphire buffered by a double layer of CeO2/Y–ZrO2. Such structures may be considered for tunable microwave filters. The top and bottom YBa2Cu3O7−δ films were well c-axis oriented, free from microcracks and had superconducting transitions Tc's in the range 86–90 K. A thin antidiffusion layer of SrTiO3 (d≈70 A(ring)) between YBa2Cu3O7−δ and BaxSr1−xTiO3 (x=0.25–0.9) promoted better crystallinity and higher Tc of the top superconducting film. An Ag/BaxSr1−xTiO3/YBa2Cu3O7−δ capacitor structure was used to determine the dielectric permittivity and the high frequency loss tan δ of the BaxSr1−xTiO3 layer. Maximum values of the permittivity of the BaxSr1−xTiO3 layers were observed around the Curie temperatures of corresponding bulk monocrystals. The dielectric permittivity of the BaxSr1−xTiO3 (x=0.25–0.75) layers depended strongly (≈20%) on an applied voltage (±2.5 V) at temperatures around 77 K. The tan δ was much higher in films than in bulk crystals. © 1995 American Institute of Physics.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.359804
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