Feasibility of a High Temperature Superconductor rf-SQUID Based on Biepitaxial Josephson Junction Technology

Recently, the observation of macroscopic quantum effects in high critical temperature superconductor (HTS) Josephson junctions (JJs) paved the way to the possible use of HTS in quantum hybrid circuits. Dissipation in HTS JJs has been proven to be below expectations, even in junction configurations designed to fully exploit the functionality of a d-wave order parameter symmetry, where low energy quasi-particles can be more harmful for coherence. We report on the design of YBaCuO rf-SQUIDs based on the properties of sub-micron biepitaxial junctions with variable inter face orientation with respect to the order parameters of the two electrodes. The study of the double well potential of such system may offer further insights for a deeper understanding of the dynamics of a HTS Josephson device. The rf-SQUID has been de signed to have independent controls for the barrier height between the wells and for the relative positions of the energy levels in different fluxoid wells. The flux state of the rf-SQUID is readout by an inductively coupled dc-SQUID magnetometer.