FIG. 1.

X-ray diffraction pattern of an AFM cantilever that was coated with a hematite thin film using oxygen plasma-assisted molecular beam epitaxy. Gold (Au) and hematite (Fe₂O₃) references are shown for comparison. The Au signal originates from a coating applied to the “backside” (see schematic inset) of the cantilever by the manufacturer. The Au coating increases laser reflectivity for the AFM's optical lever detection, but it does not interfere with measurements of the force between the protein and hematite.