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Samples of epitaxial thin layers of Sr2Co2Fe28O46 hexaferrite were studied. Hexaferrites are important materials for permanent or soft magnets, magnetic recording and data storage media, and components in electrical devices, particularly those operating at microwave/GHz frequencies.
Magnetization and magnetic domain structure were investigated using Lorentz transmission electron microscopy (LTEM) at various temperatures. With changing temperature, the magnitude of magnetization in the (0001) plane changed at ~355 K, while that along the [0001] direction remained almost unchanged, suggesting a spin reorientation transition.
Description
Figure: Lorentz-TEM over-focus images taken at (a) 293 K, (b) 333 K, (c) 433 K, and (d) 293 K (by cooling). The yellow and green arrows indicate the position of light and dark domain walls, respectively. The right- and left-side images of each figure show the magnetization distribution in the area surrounded by the red-line squares. Here, the magnitude and directions of the local magnetic moments are represented by brightness and color phase, referring to the color wheel, and additionally illustrated by white arrows inside the maps.
Soroka, M. et al. Journal of the European Ceramic Society 43 (2023) 6916.