If we use as you said, then Where the  electron beam will discharges after interaction with matter ...

The suggest of Mr Kalambate is correct but in such case you will need a microscope with a biprism. The number of the in increasing but still not so common.

Other possibility is try to get a Cs-corrected microscope, and use the last lens as a pseudo-lorentz lens. It works really good.

Thank dear

I need to understand what you want to learn from the sample. If you only want to study the structure and morphology you can insert the sample with a good fixation in the sample holder. Only implication is that when you move the sample it will influence the magnetic field in the pole piece and you have to retune rotation center and astigmatism locally on every area of interest you want to take an image.

If you want to look at the magnetic structure you cannot use a mode with objective lens on since you destroy the magnetic structure of the material. You have to go to LM mode (low mag mode). Then the objective lens is switched off and there is almost no magnetic field in the pole piece except some remanence of the FeCo poles. Here you can use a biprism to visualize the magnetic structures for example magnetic domains in steels.  Or you use Fresnell imaging techniques  by defocussing the sample (about a few microns underfocus) to see the magnetic domain walls(called on axis holography).See the following link.

http://lma.unizar.es/research/transmission-electron-microscopy-tem/tem-magnetic-materials/

Only drawback in LM mode - where the diffraction lens is typically used - is that the resolution due to the diffraction lens Cs (typically meters) is degraded compared to objective lens on mode (Cs typically mm). Resolution is around 5-10nm depending on the acceleration voltage (200-300kV). This is good enough for omains in magnitc metals, but does not work for skyrmion research for example. Only if you need nm or sub nm resolution the Lorenz lens is required. LM mode will not deliver such a resolution.

Best

Bert

The most straightforward magnetic TEM imaging technique is Lorentz microscopy. Although it presents multiple variants, Lorentz microscopy in Fresnel mode is by far the most useful and widely used. Defocused Fresnel images present magnetic contrast (bright/dark lines) at the position of the magnetic domain walls, the strength of this contrast depending on the relative orientation of the magnetization at both sides of the domain wall.