  The interplay of a potential and magnetic disorder in superconductors remains
an active field of research for decades. Within the framework of the Usadel
equation, we study the local density of states near a solitary classical
magnetic impurity in a dirty superconducting film. We find that a potential
disorder results in broadening of the delta-function in the local density of
states at the Yu-Shiba-Rusinov (YSR) energy. This broadening is proportional to
the square root of a normal-state spreading resistance of the film. We
demonstrate that mesoscopic fluctuations caused by a potential disorder affect
crucially a profile of the local density of states in the vicinity of the YSR
energy. In addition, we demonstrate that a scanning-tunneling-microscopy tip
can mask an YSR feature in the local density of states. Also, we study the
local density of states near a chain of magnetic impurities situated in the
normal region of a dirty superconductor/normal-metal junction. We find a
resonance in the local density of states near the YSR energy. The energy scale
of the resonant peak is controlled by the square root of the film resistance
per square in the normal state.

Mesoscale and Nanoscale Physics;Superconductivity