Near-field microwave microscopy has been used as a non-destructive tool for current distribution mapping in high-Tc superconductors and other conducting films at room temperature. The focused microwave emitted from the tip of a near-field scanning microwave microprobe is absorbed in the thin film in a small spot of size approximately same as the size of the probe tip. The heat will spread into the adjacent regions in the thin film sample through thermal diffusion. The temperature rise due to local heating will lead to the change in the local resistivity of the sample which results in a...