Magnetic force microscopy. A short review

Abstract

Magnetic force microscopy (MFM) is a scanned tip technique for imaging magnetic domain structure at the surface of magnetic materials with high spatial resolution. Different versions of the technique are reviewed, according to the type of measured interaction between tip and sample, including force, force gradient and dynamic interactions. Various materials have been imaged, including some of particular importance to the microelectronic industry, with spatial resolution varying from 100 nm for soft materials (Permalloy NiFe), down to 10 nm for hard materials (FeNdB). Theoretical calculations explain the contrast mechanisms: Measurements are correlated to the expected magnetic field from recording heads, from recorded domains in thin film disks, and recently from magnetic domain boundaries such as Bloch walls.