Transmission Electron Microscopy Study of Magnetic Domain of Cobalt-Samarium Thin Films Fabricated Using DC Magnetron Sputtering Technique


Alloys of cobalt samarium (Co-Sm) in the form of thin films were fabricated using dc magnetron sputtering technique. The films were fabricated as a function of samarium concentration ranging from 0 to 28 at.% in order to investigate the relationship between microstructure, coercivity and magnetic domain structure. Magnetic domain structures in the films have been studied by Lorentz microscopy using transmission electron microscopy (TEM). In this technique, the TEM was operated in the defocused mode. The results show that the magnetic image of Co90Sm10 film has fairly coarse structure with magnetization ripple and the domains ranging over 200-300 nm. The domain size is much larger than the grain size of Co90Sm10 film. The “multiparticle” or interaction domains suggested that there is strong exchange coupling between the magnetization of the neighbouring grains inside each of them. The hysteresis loop for this film shows a small coercivity with high magnetization value and high loop squareness, indicating a greater proportion of magnetic material. 

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