  Measuring magnetic moments in ferromagnetic materials with atomic column
resolution is theoretically possible using the electron magnetic circular
dichroism (EMCD) technique in a (scanning) transmission electron microscope
((S)TEM). However, experimental and data processing hurdles currently hamper
the realization of this goal. Experimentally, the sample must be tilted to a
zone-axis orientation, yielding a complex distribution of magnetic scattering
intensity, and the same sample region must be scanned multiple times with
sub-atomic spatial registration necessary at each pass. Furthermore, the weak
nature of the EMCD signal requires advanced data processing techniques to
reliably detect and quantify the result. In this manuscript, we detail our
experimental and data processing progress towards achieving single-pass
zone-axis EMCD using a patterned aperture. First, we provide a comprehensive
data acquisition and analysis strategy for this and other EMCD experiments that
should scale down to atomic resolution experiments. Second, we demonstrate
that, at low spatial resolution, promising EMCD candidate signals can be
extracted, and that these are sensitive to both crystallographic orientation
and momentum transfer.
