Domain Structure in Single-Crystal Thin Films of Iron

Abstract

Domain patterns of single crystal films of iron, evaporated onto MgO cleavage surfaces, were observed by the Bitter technique. Epitaxy of them was perfect and the magneto-crystalline anisotropy constant K 1 of these films determined by torque measurement was almost the same as that of bulk materials. The observed domain configuration of the films is similar to that found on bulk crystals. However, some differences between them are caused from the thinness of the films. Predominance of the 90° walls and the configuration of two types of crossing of 90° walls in a cubic film are discussed. Using a new type of colloid, electron microscopic observations of walls were undertaken to find out their fine structure. From this observation it is confirmed that the walls in the films (<1000 Å thick) are the Néel type, and the Bloch lines should appear in 180° Néel walls. The reason why the cross-tie walls are not found in cubic crystal films is discussed.