In this communication we have observed that magnetic hysteresis loops for the 6 nm, 14 nm, 20 nm and 24 nm thin as-deposited & annealed CoFeB films for two indicated directions (easy axis & hard axis) of the magnetic field applied within the film plane. The magnetization loop for 20 nm CoFeB film show noticeable double step magnetization switching behavior when the magnetic field is applied at 90° away from the Easy axis. This switching in magnetization behavior in a single layer CoFeB thin film could be a result of magnetic anisotropy caused by bond orientational anisotropy (BOA). But when the MOKE M-H loop recorded on annealed film (300°C) along the same direction in the crystallized samples did not prominantly show such double switching behavior. The possible reason for the partial disappearance of this behavior during magnetization in switching in the crystallized samples might lie in the microstructural changes that took place during the crystallization of the 20 nm CoFeB thin film. The calculated value of the Hk decreases with increase in thicknesses of as-deposited and annealed films. In the thickest films, interface uniaxial magnetic anisotropy (UMA) is found to be significantly weaker than the volume anisotropy.
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