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Magnetic Force Microscopy

Basic MFM Operation

Rev. D Dimension 3100 Manual 263

Phase Detection

Set the Channel 2 image Data type to Phase; Z range to 3 degrees; and Line direction to

Retrace.

Note: It is important that the Scan direction be set to Retrace for both the main and

interleave scans. If instead it is set to Trace, a band may appear along the left

side of the images due to the time taken for the tip to move between the surface

and the lift scan height.

Amplitude Detection

1. Set the Channel 2 image Data type to Amplitude, Z range to 1nm, and Line direction to

Retrace.

2. Change Interleave mode to Enable to invoke LiftMode.

3. Set the Channel 2 Scan line to Interleave to display the interleaved data.

Note: This can only be done after Interleave mode is Enabled. A magnetic force

gradient image similar to that shown on the right of Figure 15.2e should appear

as the Channel 2 image. The alternating dark and light stripes represent the

recorded magnetic information, signifying a varying resonant frequency and

magnetic force gradient on the tip.

Note: Keep the Setpoint as large as possible while consistent with a good image.

Wider scans (> 25µm) will reveal separate tracks in which the magnetic stripes

are at different angles

Frequency Modulation

With the Extender Electronics Module, it may be desirable to use frequency modulation. This

activates a feedback loop which modulates the Drive Frequency to keep the cantilever phase lag at

90 degrees relative to the drive, corresponding to resonance. The frequency Data Type displays the

resulting shift in Drive Frequency in Hz, and gives the most direct, quantitative image of force

gradients.

To enable frequency modulation, follow the procedure above for obtaining an MFM image with

phase detection with the following modiﬁcations:

1. In the Interleave Controls panel, set the Input Feedback to Frequency. Turn on this

parameter by selecting the gray button next to Frequency. When selected, the gray button

becomes green, indicating the control is on.

2. Switch the Channel 2 image Data type to Frequency. Try a Data scale (frequency shift) of

approximately 10 Hz.

3. Select Other Controls, then adjust the frequency modulation gains:

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Dell 3100 Spezifikationen Seite 283