Introduction Tomlinson Movie Macroscopic Friction The law of Leonardo (da Vinci) The law of Euler and Amontons The law of Coulomb Historical abstract Asperities Adhesion models Friction Force Microscopy Principle of measuring Measuring Topology Measuring Friction Both Channels Calibration Dissipation Self assessment Tomlinson's mechanism Phenomenology I Phenomenology II Mechanical adiabaticity Distinguish positions Playing Tomlinson Friction - a pinning problem 2D Friction Critical Curves Historical Background Research Projects Simulator Applet The first Picture The Panels Parameters Post processing Statistics Glossary Textbook

Calibration

 Measuring the dimensions of the tip and its lever by Scanning Electron Microscopy

In order to determine the force out of the beam deflection, the precise optics as well as the spring constants of the cantilever have to be known.

The calibration procedure is one of the essential parts of FFM-experiments. Each cantilever should be characterized accurately. Manufacturer's data are usually not sufficient and can lead to errors of up to a factor 10. Thus, each cantilever has to be characterized. One way is to use an electron microscope and to deterimine all the relevant parameters, such as: Tip radius R; heigth of tip h ; width, thickness and length of cantilever (w/, t, l) and position of tip on the cantilever. In addition, elastic constants are needed: Youngs modulus E, shear modulus G. Having determined all these parameters, the normal spring constant cB and the torsion spring constant ct for a rectangular cantilever are given by:

From Scanning Electron Microscopy the dimensions of the cantilever can be determined in order to compute its spring constant. One can get more precise results by making use of the resonance frequency instead of the thickness of the lever, since the thickness is a very important property which can be determined only with troubles.

Both Channels                  Dissipation