Fabrication and characterization of bi-based intrinsic Josephson junctions for biomedical applications

Discovery of the carrier injection effect has allowed us to study the superconducting intrinsic Josephson effect from a different perspective. In this thesis, we showed that the some properties such as the critical temperature, the c-axis resistivity, the transparency of tunneling barrier and the critical current density in the intrinsic Josephson junctions can be tuned in a controlled way from the underdoped state to the overdoped state. These changes occurred in the superconducting properties can be explained by the fact that the charges are trapped in the BiO and the SrO layer and then the charge carriers (holes) are induced in the superconducting planes. The aim of this thesis is to study the doping effect by the charge carrier injection in the Bi-based HTc superconducting whiskers and to investigate the use of the intrinsic Josephson junctions as a biomedical sensor. The cross junctions prepared using two whiskers were modified by the charge carrier injection, which is the first in literature. Additionally, it was showed that the cross junctions displayed ideal junction characteristics and reproducible. On the other hand, some features such as the electron trapping mechanism, the superconducting energy gap and the pseudogap phase are also discussed, which are currently under discussion in literature. The I-V characteristics of the currents flowing along the c-axis were analyzed and information about the interlayer charge transport mechanism was given. Temperature dependence of the interlayer charge transport in the BSCCO whiskers single-crystals exhibited a crossover from thermally activated behavior to the interlayer quantum tunneling below the superconducting transition temperature.