Local modification of the thin YBa₂Cu₃O_7-y microstrips by the voltage-biased atomic force microscope tip

The atomic force microscope (AFM) tip biased at around -15 V is found to be capable of locally modifying the entire thickness of 40-nm-thick semiconducting or superconducting YBa₂Cu₃O_7-y microstrips in air. We show, using combined electrical and AFM measurements, that the local regions underneath the surface of the semiconducting or superconducting YBa₂Cu₃O_7-y microstrips are transformed into either nonconducting or nonsuperconducting regions, respectively, upon applying the negatively biased AFM tip. The conductance of the nonsuperconducting regions is also found to be comparable to that of the superconducting regions before modification at 298 K.