Studies of YBa2Cu3O6+x degradation and surface conductivity properties by Scanning Spreading Resistance Microscopy

► Local surface conductivity of c-axis oriented YBa2Cu3O6+x thin films was studied by SSRM. ► The surface conductivity is highly inhomogeneous on micro- and nano-scale. ► Numerous regions of highly enhanced conductivity compared to the surroundings were observed. ► Size of the low-resistance regions increases with increasing of the applied voltage. ► Surface degradation over time was observed as a decrease of the average surface conductivity.