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Magnetic Force Microscopy

Advanced MFM Operation

Rev. D Dimension 3100 Manual 265

Figure 15.3a High-resolution Magnetic Force Gradient Image

15.3.2 Fine Tuning Interleave Controls

Certain scanning parameters found under Interleave Controls can be set to values in the Interleave

(Lift) scan that differ from the values in the main scan. These parameters are enabled by clicking on

the circular ﬂag to the immediate left of the desired Interleave control, toggling its state from Off

(gray bullet) to On (green bullet). When the ﬂag is set to Off, the main scan control parameter

setting takes precedence. When the ﬂag is set to On the displayed Interleave scan value is active,

overriding the main scan value.

15.3.3 Drive Amplitude

For MFM, of particular use is the Interleave Drive Amplitude. This parameter can affect a

magnetic force image in a variety of ways.

• Increasing the Drive Amplitude can improve the signal-to-noise ratio when using phase

detection or frequency modulation. This is because intrinsic, low-level noise interferes

less when measuring the phase of a larger cantilever oscillation amplitude and hence

stronger photodetector output. As an illustration, try setting the Interleave Drive

Amplitude to 0; the resulting phase image will be pure noise because one cannot

measure the phase of a non-oscillating cantilever.

• In LiftMode, the Interleave Drive Amplitude can often be set to a value larger than in

the main scan, thus giving optimal signal-to-noise. In some cases this is beneﬁcial as

long as the Drive Amplitude is not increased to the extent that the tip strikes the surface

on the low point of its swing. The signatures of tip-sample contact are white and black

spots in the image, or, in extreme cases, noisy, high-contrast streaks across the whole

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