AFM cantilevers with spherical tip of millimeter size

The fabrication and application of a new type of cantilever for atomic force microscopes are presented. The beams of the cantilevers are made from a thin sheet of beryllium copper, featuring a bending stiffness in a wide range of 2-1900 N m−1, onto which a ball is cemented, whose diameter can be in the range of 0.1-1 mm. The basic properties of the cantilevers (longitudinal and torsional rigidity, tip diameter and material) can be easily changed. The cost of fabricating the cantilevers is considerably lower compared to their commercial counterparts, whereas their quality is approximately the same. Using these cantilevers, it is possible to perform measurements of the tribological properties of material pairs such as steel-molybdenum disulfide (MoS2), steel-lead (Pb) and polymer-polymer. The larger radius of the cantilever tip also enables measurements of viscosity, and decreases the contact pressure, which is crucial in measurements of biological samples.