Process:

An Atomic Force Microscope gathers 3 dimensional topographic information about the sample it is scanning by probing its surface structure with a sharp vibrating tip. As the tip is scanned across, the vertical movements of the tip are recorded and used to build a 3 dimensional map. The lateral resolution of the image can be as small as the tip radius (typically 5-15 nm), and the vertical resolution can be on the order of angstroms.

A standard AFM microscope can analyze a sample between 10-20 cm2 to a resolution of less than .2 nanometers (billionths of a meter). It can accept solid samples or have irregular samples epoxied or glued onto a slide.

AFM is considered a non-destructive means of scanning, because the force used to probe the sample is so small.  It also has the advantage of little to no preparation time to prepare the sample. Data can also help determine properties such as stiffness and friction of the sample.

 Atomic Force Microscope image of the surface of a SrTiO3 crytstal etched in 5% HF solution.

Process:

Magnetic Resonance Force Microscopy (MRFM) uses a flexible cantilever in which the sample is placed. It is positioned near a magnetic tip, which produces a magnetic field. The RF coil excites a small fraction of the sample, which causes a force between the sample and magnet's tip, and the modulation is measured by detecting sample deflections with the interferometer. This type of instrument can measure distances in terms of microns (one millionth of a meter) but work is being made because of its potential with true three dimensional, subsurface imaging with chemical specifity.