Researchers from NIST have validated a simpler method for calibrating lateral sensitivity in atomic force microscopes (AFMs) that agrees with an earlier NIST method to within 5%. This equivalence between two independent methods represents an important step towards traceable accuracy in lateral force microscopy.
The new “Diamagnetic Lateral Force Calibrator” (D-LFC) method, developed at Brown University, requires fewer independent measurements compared to the NIST “HammerHead” (HH) method. The D-LFC method uses a piece of graphite that levitates in a magnetic field, allowing the AFM cantilever to twist when a lateral force is applied, leading to a change in the lateral signal that can be used to calibrate friction directly.
While the D-LFC method is preferable for most circumstances due to its greater precision, the HH method can be advantageous if contact between the probe tip and the calibration surface must be avoided. The researchers believe that the overall accuracy and comparability of these two methods establishes the importance of the D-LFC method as a valuable tool for unifying quantitative measurements of friction at the nanoscale, and establishes a potential path towards the development of lateral force standards.
Keywords: Calibration, Friction, Atomic Force Microscope, Lateral Force, Nanoscale
