A 0.5-T pure-in-plane-field magnetizing holder for in-situ Lorentz microscopy

A side-entry specimen holder capable of applying a 0.5-tesla in-plane magnetic-induction field for in-situ transmission electron microscopy was developed. Three miniaturized electromagnets with 300 × 300-µm pole area and 180-µm pole gap are stacked along the electron-beam path in the holder. The middle magnet is used for magnetizing the specimen, which is inserted into the pole gap by using a 40-µm-width cantilever for atomic-force microscopy. The upper and lower magnets are used to keep the electron beam parallel to the optical axis. Magnetic-field magnitude was determined on the basis of experimentally measured electron-deflection angles and induction-field profiles along the electron-beam path calculated by finite element electromagnetic simulation. Magnetization reversal in 300-nm-thick Nd-Fe-B magnets from the saturated state was in-situ observed by using the holder and a 1-MeV cold-field-emission transmission electron microscope. The observation revealed that domain-wall pinning occurred in different manners at the c-plane and non-c-plane grain boundaries. The holder was thereby shown to be useful for analysis of magnetization-reversal behaviors of hard magnetic materials.