Reverse modelling for Lorentz transmission electron microscopy*

Lorentz Transmission Electron Microscopy (LTEM) is a versatile measurement technique that can probe the magnetic configuration of thin films under a wide variety of experimental conditions. One limitation of this measurement technique is that it is only sensitive to projection of the sample’s magnetic moment onto a two dimensional plane that is perpendicular to an electron beam which is passed through the sample. We have developed an algorithm which linearizes the relationship between the experimental sample and measured phase change. The resulting underdetermined system can be augmented by solving to two or more different measurements simultaneously and can be solved using iterative optimizers. We apply this to measurements of NdFeB to obtain a magnetic configuration which would not be discoverable by treating measurements individually.