Master's Thesis: "Simultaneous Creation of Double-barrier Superconducting Junctions with Different Intermediate Film Thickness and Junction Evaluation by Two-dimensional Scanning of External Magnetic Field"
Doctoral Dissertation: "Study on 3D Magnetic Field Modulation Property of Josephson Junction"

Josephson junction is applied to a highly sensitive magnetometer called a superconducting quantum interferometer that measures biomagnetism. In my master's program, I developed my undergraduate research to create a double-barrier Josephson junction with a structure in which two Josephson junctions were stacked. Then we investigated how the current-voltage properties and two-dimensional magnetic field modulation property of the double-barrier Josephson junction change when the junction interval between the two Josephson junctions is changed.
Specifically, we found a new phenomenon where the properties change significantly when the distance between the two junctions is 5nm or less, and superconducting current does not flow when there is no Nb layer between the junctions. In my doctoral program, we investigated in more detail on how the magnetic flux trapped in the superconducting thin film and Josephson junction affect the properties of Josephson junction when the sample is cooled to the superconducting state. A strong magnetic field was applied perpendicularly to the joint surface to trap the magnetic flux quantum in the Josephson junction or superconducting thin film, and the dependence of the vertical gradient of the Josephson current was measured. Currently, we are observing the magnetic flux quantum trapped in this Josephson junction.