Application V
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Scan Range: 5 µm × 5 µm
Left Data Type: topography / Data Range: 20 nm
Right Data Type: MFM phase / Data Range: 10 deg
The left image shows the surface topography of a computer harddisk
measured in tapping mode. The upper part of the right image shows the
magnetic data structures as they were recorded simultaneously in
standard mode, whereas in the lower part of the image Q-Control was
activated. It is clearly visible, that the application of Q-Control
leads to a significant improvement of the overall sensitivity and
thereby to an amplification of the magnetic contrast. Please note that
except for that Q-factor all parameters, e.g. oscillation amplitude,
lift height and scan speed, were kept constant during the entire scan.
Further investigations revealed, that in particular the signal-to-noise
ratio of such measurements on magnetic fields can be improved
significantly:
This analysis of measurements on a magnetic tape shows that the signal amplitude (upper diagrams), i.e the image contrast, was increased by a factor of 12.4 by Q-Control. However, in order to assess the improvement in overall sensitvity it is more relevant to analyse the signal-to-noise ratio. Just by looking at the cross-sections it is already obvious that Q-Control leads to an significant improvement, i.e. less noise. The detailed statistical analysis of averaged data (lower diagrams) revealed an increase of the signal-to-noise ratio by a factor of 2.3.
This analysis of measurements on a magnetic tape shows that the signal amplitude (upper diagrams), i.e the image contrast, was increased by a factor of 12.4 by Q-Control. However, in order to assess the improvement in overall sensitvity it is more relevant to analyse the signal-to-noise ratio. Just by looking at the cross-sections it is already obvious that Q-Control leads to an significant improvement, i.e. less noise. The detailed statistical analysis of averaged data (lower diagrams) revealed an increase of the signal-to-noise ratio by a factor of 2.3.