Chemistry Reference
In-Depth Information
Fig. 5.10
Two-dimensional
instrumental response
function determined by
iterative fitting. (
a
)The
two-dimensional response
function is shown on a 40
μ
m
scale. (
b
)Asliceofthe
two-dimensional response
function shown in (
a
). The
general broad features are
similar to the one-dimens-
ional response function found
earlier. The spike was added
to allow sufficient resolution
in the vicinity of the small
defect structures
at a large tip-sample separation to the lower separation of interest, where it is
broader.
Thus, given data from a sample where the true signal is known, as is the case
for regions from a straight wire far from the defect, the deconvolution algorithm
may be used to determine the instrumental response. An example of an instrumental
response function determined in this way is shown in Fig.
5.10
. In the following, we
will discuss the determination of current distributions from MFM data from which
the instrumental broadening has been removed via deconvolution.
5.3.4 Image Inversion
Following deconvolution to remove the instrumental broadening, it is possible to
quantify the distribution of currents underlying the MFM images by inverting the
data. Techniques of inversion from the magnetic field have been well developed
