Resolution of an emission electron microscope in the presence of magnetic fields on the object

The known Brüche-Recknagel formula for determining the resolving power of an emission electron microscope (EEM) was derived assuming idealized conditions: the object surface was planar, and the accelerating electric field was homogeneous. However, deviations from these conditions will deteriorate the resolving power. This can be caused by a surface topography as well as local electric or magnetic fields on the object surface. In the present paper the resolving power of an EEM is calculated for the case when there are local magnetic fields on the object surface. The deterioration of the resolving power will then depend on the local field strength not only in the given point of the object surface, but also in adjacent regions. The estimations performed show that the lateral resolution in EEM under the influence of magnetic microfields of real ferromagnets can be several times worse than in the case of the absence of these fields.