Licentiate thesis: Confinement and resonant phenomena in small Bi2Sr2CaCu2O8 mesa structures
by
Sven-Olof Katterwe(Stockholm University, Department of Physics)
→
Europe/Stockholm
A2:1041
A2:1041
Description
In this thesis, intrinsic Josephson junctions, naturally formed in the strongly anisotropic high-temperature superconductor Bi2Sr2CaCu2O8, are studied experimentally. Small mesa structures are fabricated on the surface of single crystals using micro and nano-fabrication tools, focused ion beam is used to reduce the mesa-area to ≈ 1 × 1 μm2.
Intrinsic tunneling spectroscopy is performed to investigate properties of charge transport between adjacent copper-oxide layers at temperatures from 14 K to 300 K.
The dependence of the critical current on parallel magnetic fields up to 4 T is studied for mesas with different sizes at a temperature of 1.6 K. Modulations similar to the Fraunhofer diffraction pattern are found.
Finally, flux-flow characteristics and resonance phenomena are studied in magnetic fields up to 17 T.
It is argued that the employed technique for miniaturization of mesas and the obtained results can be useful for better understanding of fundamental properties of high-temperature superconductors and for realization of a coherent flux-flow oscillator in the important THz frequency range.
