Lateral Force Mode
Advanced LFM Operation
170
MultiMode SPM Instruction Manual
Rev. B
10.2.2 Tip selection
The analog-to-digital converter on the auxiliary input channel which is used for LFM data has a
maximum input range of ±10V. This, and the anticipated interaction between tip and sample de
fi
ne
the selection of the cantilever to be used for the measurement.
The 200µm cantilever with wide legs provides a good starting point for frictional measurements. It
is
fl
exible enough to provide reasonable signal levels on samples with moderate friction. If the
signal e 10.00V with the 200µm wide-legged cantilever, one of the stiffer 100µm
cantilevers should be used. If the signal level is too small, the narrow-legged 200µm cantilever will
provide a larger signal.
10.2.3 Understanding the LFM Signal
To understand LFM, examine a sample’s trace and retrace in scope mode.
below
illustrates the movement of the tip as it encounters friction during a scan.
Figure 10.2b
Example of Frictional Forces on Tip During Scan (Front View)
1
Horizontal
De
fl
ection
10
2
9
3
8
7
5
6
4
Trace
Retrace
= Higher Frictional Areas
