Spectral Characteristics of a Fully Superconducting SQUIPT

We consider properties of a fully superconducting variant of the superconducting quantum-interference proximity transistor, a magnetic-flux sensor. We study the density of states in a finite-size superconducting metal wire in the diffusive limit, and how it depends on the phase gradient of the order parameter. We describe the dependence on the junction length and the interface transparency, and we discuss properties relevant for using the structure in magnetic-flux-detection applications.