Albanova Nano-Fab-Lab, MFM

Albanova Nano-Fab-Lab, SPM/AFM

MFM measurements using the Multimode SPM

MFM using Dimension 3100 on 300 GB disk platter

Some very short notes on how to do MFM with the Multimode and the Nanoscope IV controller.
More info can be found in the manual for the Nanoscope IV controller. Please note that the "main" manual refers to the Nanoscope III controller in many places.

Important settings:

Magnetize the tip with cylindrical permanent magnet
Set up for normal tapping mode
Use Autotune to find tapping frequency
Interleave must be active
Interleave Mode must be Lift
Input Feedback for Interleave Mode should be Frequency
Lift Start Height should be 0
Lift Scan Height should be 100 nm - 30 nm,
Start at 100 nm and decrease slowly and carefully
until magnetic image is good.
Too small height result in crosstalk from height image.
Set Channel 2 Data Type to Phase
Set Channel 2 Scan Line to Interleave
Set Channel 2 Datascale to about 2°

Alternatively for Channel 2:

Set Channel 2 Data Type to Frequency
Set Channel 2 Scan Line to Interleave
Set Channel 2 Datascale to about 20-40 Hz

There is a test sample provided by Veeco, a piece of magnetic tape.

Here is a picture of the magnetic tape sample provided by Veeco. The Channel 2 Data Type was set to Phase for the lower part of the image and set to Frequency for the upper part of the image. Please note the difference in noise level, much lower noise level for the Frequency setting. This is however strongly dependent of the sample, it can be the other way around for other samples. Both settings should be tried.

Here are the parameter settings for the MFM picture above.

MFM on a hard disk drive, 500GB capacity

Fine magnetic pattern from a high density hard disk drive, 500 GB, 3.5 inch diameter.


Height image showing a very smooth surface	Phase image showing magnetic domains

Please note that the lift height is much lower than the examples above, here it is only about 10 nm. Image size 1 µm, scan speed 2 Hz.

MFM on a hard disk drive, 40GB capacity


Height image showing a rather dirty surface, it has been exposed to normal office environment for some days prior to scanning.	Phase image showing magnetic domains. Please note that the magentic tracks are about 3-4 times wider on this lower capacity disk.

Sample and scanning Daniel Forchheimer, 2011-05-17

Albanova NanoFabLab
Anders Liljeborg