Fig. 1

Temperature dependence of resistivity upon electron irradiation. Resistivities of four different samples: R1 (0, 0.23, 0.47, 0.72, 0.95, 1.18, 1.4, 1.7, and 2.4 C cm⁻²), R2 (0, 1.57 C cm⁻²), R3 (0, 3.67 C cm⁻²), and R4 (0, 4.18 C cm⁻²). Note that all 0-dose curves for samples R1, R2, R3, and R4 are coincident. Overall resistivity increase with increasing dose was consistently seen for all samples, as shown by the arrows. The inset shows in-situ measurement of resistivity of sample R1 as a function of dose during electron irradiation at 22 K. The blue arrows indicate stops in irradiation, during which the sample was extracted from the irradiation chamber and characterized. Partial annealing of about 30–40% of resistivity increase occurred on warming the sample to room temperature and subsequently cooling down to 22 K