An oscillatory transition from normal to superconducting state in mesoscopic Al samples

Temperature dependence of resistance, R(T), has been measured for different perpendicular magnetic fields in mesoscopic Al squares. An anomalous oscillatory resistive transition into the superconducting state has been found. This transition is characterized by the appearance of several well defined maxima on the R(T) curve in the vicinity of the superconducting transition temperature. We suggest that these R(T) maxima are caused by destructive quantum interference processes, implying the formation of superconducting but non-current-carrying states in the mesoscopic Al samples. (orig.)