Fabrication and evaluation of the superconducting d-dot device manufactured with the Y$_{0.9}$La$_{0.1}$Ba$_{1.9}$Cu$_{3}$O$_{y}$ thin film by a DC Sputtering method

The d-dot device is composed of a square shaped d-wave superconductor buried into a s-wave superconductor thin film. The internal phase difference at neighboring square side junction causes a half-quantum-flux at each corner of square of d-wave superconductor. We have developed the method for preparing the d-dot with YBCO thin film by PLD method previously. In the present work, we employed a DC sputtered Y$_{0.9}$La$_{0.1}$Ba$_{1.9}$Cu$_{3}$O$_{y}$ thin film with ramp edge, which is a well-established standard process for fabricating high-T$_c$ single flux quantum (SFQ) device of SRL- ISTEC. Evaluations of this d-dot device are performed by I-V and R-T measurements. The magnetic flux structure has been investigated by a scanning SQUID microscope.