Nanoscale Characterization of Magnetoresistive Tunnel Junctions Using a Conducting Atomic Force Microscope

An AFM equipped with a conductive-coated tip and sensitive current detector can be used to measure tunneling current through thin (1 \u2014 3 nm) aluminum oxide layers formed on a bottom, conducting electrode. From these measurements, the spatial current distribution and the product of area and resistance for different thicknesses of A1Ox films can be found. The effects of different tip coatings, sample preparations methods, and AFM techniques will be experimentally determined and discussed. Also, a model is to be presented for the interpretation of the tunneling current results.