


1. Sader Method for a set of rectangular/nonrectangular cantilevers. Introduction
Experimental determination of the spring constants of Atomic Force Microscope
(AFM) cantilevers is of fundamental importance in many applications of the AFM.
For rectangular AFM cantilevers, both the normal and torsional spring constants
can be measured using the unloaded resonance techniques detailed
below.
The Sader method was extended to enable simultaneous calibration of
the torsional spring constant of rectangular AFM cantilevers (Rev. Sci.
Instrum., 75, 1988 (2004)). This extension, referred to as the
Torsional Sader method, enables calibration of the torsional spring
constant using an identical experimental methodology.
Recently, the physical basis for the method was elucidated and its extension to small elastic bodies
of arbitrary shape presented (J. Appl. Phys., 97, 124903 (2005)). This was also applied to a
series of commercially available nonrectangular cantilevers (Rev. Sci. Instrum., 83, 103705 (2012)).
The advantages of these techniques are that they are rapid to use, simple to
implement experimentally, and importantly, are noninvasive and nondestructive.
In order to assist users who would like to make use of these techniques,
Java applets, iPhone and Wolfram CDF Player web apps, have been created which
perform the calculations online.
In addition, Mathematica
® notebooks for calculating the spring constants using the
aforementioned techniques are available for download.
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