Visualization of Electric Current Flow by Use of Magnetic Force Microscopy

We present a two-dimensional (2D) imaging of electric current flow in nanoscale range obtained for planar structures. Experiments were performed at current densities of 10 5 –10 6 A/cm 2 for ∼1 - # # μ # # m-wide current-carrying metallic stripe. The images were obtained by use of magnetic force microscopy (MFM) as a sensor to measure a magnetic response of current flow. The 2D current mapping was reconstructed from MFM phase images by numerical inversion of Biot-Savart law. By using such method, we obtained the parallel and perpendicular components of the current as well as module of total current with the spatial resolution better than 100 nm. We clearly observed the changes of X and Y components of current density related to changes in the cross-section or form of the structures. Developed magneto-transport techniques can be used for detection and control of the current flow in real nano-electronic devices for studying of defects of current paths in nano-stripes due to, for example, electromigration processes and in other applications.