Magnetization process in sm fine powders studied using lorentz microscopy and electron holography

The magnetization process for Sm₂Fe₁₇N₃ fine powders was studied by Lorentz microscopy and electron holography. In ex situ observations under the external magnetic field produced by an electromagnet, the change of the domain wall position was observed by Lorentz microscopy, while the drastic change in the distribution of lines of magnetic flux outside the fine powders was clarified by electron holography. Through in Situ observations with a piezodriving holder with localized magnetic field produced by a sharp magnetic needle, the shift of domain walls was observed in real time by Lorentz microscopy. Finally, on the basis of Lorentz microscopy observations, the magnetization process of Sm₂Fe₁₇N ₃ fine powders was briefly discussed taking into account a hysteresis loop.