SFM-Based Stiffness Mapping in Force Modulation Microscopy FMM Mode

SFM-Based Stiffness Mapping in Force Modulation Microscopy (FMM) Mode 

The reduced modulus, Efs, is given in terms of the Young s modulus values of both the tip, Et, and the sample material. Eg, by Eq. (3), where v, and Vg denote the Poisson s ratios of tip and sample material, respectively [20]. 

A prerequisite for the apphcation of the Hertz or Johnson-KendaU-Roberts (JKR) contact models is that the contact radius a is much smaller than the radius of curvature R of the apex of the tip [21]. 

In order to determine the local mechanical properties such as the hardness and modulus of non-flat samples or heterogeneous multiphase materials, a DSI system was integrated in a scanning device. This system combines SFM-like topography imaging with the ability of DSI tests to be performed at selected areas of interest by using a well-defined diamond tip. 

Basically, a force transducer (Triboindenter Hysitron Inc., Minneapolis, MN) was mounted on the fixed outer frame of a piezoelectrically driven xy-scanning stage (max. displacement 175 pm) with a large opening (Fig. 8.2). The sample is 

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