Local modification of the thin YBa2Cu3O7-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 semicondu cting or superconducting YBa2Cu3O7-y microstrips in air. We show, using com bined electrical and AFM measurements, that the local regions underneath th e surface of the semiconducting or superconducting YBa2Cu3O7-y microstrips are transformed into either nonconducting or nonsuperconducting regions, re spectively, upon applying the negatively biased AFM tip. The conductance of the nonsuperconducting regions is also found to be comparable to that of t he superconducting regions before modification at 298 K. (C) 2000 American Institute of Physics. [S0003-6951(00)02104-5].