32. Click on Fit Data. A new red (smoothed) curve will appear (see
Note 10).
33. Go to Calculate Spring K (N/m) and save in the parameters.
34. Press Withdraw to move the cantilever out of the surface.
35. Go to Navigate and click on Sample Load Position to lift the
AFM head. Next, remove the sapphire sample (do not turn off
the software).
3.4 Acquiring
Images and Force
Curves
1. Set the directory where the files are going to be saved.
2. Take the AFM head out, place the slide with the section on the
microscope stage, and stabilize the slide with magnetic clamps
(see Note 11).
3. Using an objective camera, move the sample to the center and
focus on the ROI in the sample (see Note 12).
4. Place the AFM head back on the microscope stage over the
sample (Fig. 3e).
5. In the Navigate window, adjust the focus on the cantilever by
moving the scan head down.
6. Using the objective camera, monitor the distance between the
tip and the sample. When the cantilever is close to the sample, it
should appear in the center of the view (Fig. 3f).
7. Define parameters in Check Parameters window (Follow PeakForce QNM User Guide, Bruker for more details):
Parameter
Comment
Scan size
Maximum scan size is 150 μm
2
Scan rate
Scan rate is inversely proportional to the scan size and
Samples/Line. It is usually not higher than 0.6 Hz
Samples/line
It defines the number of pixels (indentations) in a line.
Use low resolution (Samples/Line: 64 or 128) for
quick overview images and use higher resolution
(Samples/Line: 256 or 512) for quantification images
Peak force
Setpoint
It is usually automatically adjusted by the software but
can be controlled manually. The value of Peak Force
Setpoint should be as small as possible
ScanAsyst auto
control
If ScanAsyst Auto Control is on, then the system
automatically adjusts PeakForce Setpoint (max force
nN), and Feedback Gain
When ScanAsyst Auto Control is set as individual, you
can adjust ScanAsyst Auto Gain, ScanAsyst Auto
Setpoint, ScanAsyst Auto Scan Rate, ScanAsyst Auto Z
limit
Peak force
amplitude
Usually it is default but can be changed if there is a
problem to retract the tip off the surface
(continued)
360
Mateusz Majda
Note 10).
33. Go to Calculate Spring K (N/m) and save in the parameters.
34. Press Withdraw to move the cantilever out of the surface.
35. Go to Navigate and click on Sample Load Position to lift the
AFM head. Next, remove the sapphire sample (do not turn off
the software).
3.4 Acquiring
Images and Force
Curves
1. Set the directory where the files are going to be saved.
2. Take the AFM head out, place the slide with the section on the
microscope stage, and stabilize the slide with magnetic clamps
(see Note 11).
3. Using an objective camera, move the sample to the center and
focus on the ROI in the sample (see Note 12).
4. Place the AFM head back on the microscope stage over the
sample (Fig. 3e).
5. In the Navigate window, adjust the focus on the cantilever by
moving the scan head down.
6. Using the objective camera, monitor the distance between the
tip and the sample. When the cantilever is close to the sample, it
should appear in the center of the view (Fig. 3f).
7. Define parameters in Check Parameters window (Follow PeakForce QNM User Guide, Bruker for more details):
Parameter
Comment
Scan size
Maximum scan size is 150 μm
2
Scan rate
Scan rate is inversely proportional to the scan size and
Samples/Line. It is usually not higher than 0.6 Hz
Samples/line
It defines the number of pixels (indentations) in a line.
Use low resolution (Samples/Line: 64 or 128) for
quick overview images and use higher resolution
(Samples/Line: 256 or 512) for quantification images
Peak force
Setpoint
It is usually automatically adjusted by the software but
can be controlled manually. The value of Peak Force
Setpoint should be as small as possible
ScanAsyst auto
control
If ScanAsyst Auto Control is on, then the system
automatically adjusts PeakForce Setpoint (max force
nN), and Feedback Gain
When ScanAsyst Auto Control is set as individual, you
can adjust ScanAsyst Auto Gain, ScanAsyst Auto
Setpoint, ScanAsyst Auto Scan Rate, ScanAsyst Auto Z
limit
Peak force
amplitude
Usually it is default but can be changed if there is a
problem to retract the tip off the surface
(continued)
360
Mateusz Majda