Search

We have discovered that there exist dynamic scaling behaviors for the nucleation and the saturation field in hysteresis loop of Co/Pt multilayer thin films. The dynamic hysteresis measurement was carried out with variation of sweeping rate of cycling fields, which reveals that not only the coercivity and the loop area, well known as the Steinmetz law, but also the nucleation and the saturation field exhibit similar scaling behaviors. We have systematically analyzed the scaling factor of nucleation, coercivity, and saturation phase with respect to the Co sublayer thickness. Local structural configuration depending on the Co sublayer thickness were examined by extended X-ray absorption fine structure, implying that damping parameter and interface effect modifies the coercivity and nucleation scaling factor but does not significantly induce the change in saturation scaling factors. [ABSTRACT FROM AUTHOR]

Time-resolved magnetic domain patterns of (Co/Pt) and (CoFeB/Pd) multi-layers with a perpendicular magnetic anisotropy are observed by means of magneto-optical microscopy, from which magnetic relaxation curves are determined via a quantitative image analysis. Interestingly, it has been observed that the relaxation processes starting with pre-existing nucleation sites, as well as starting from a fully saturated state, are well explained based on the Fatuzzo–Labrune model, although the pre-existing nucleation sites significantly modify the magnetization reversal behaviors. [ABSTRACT FROM AUTHOR]

Time-dependent magnetic domain patterns of Co/Pt multilayer with a perpendicular magnetic anisotropy has been directly observed by a magneto-optical Kerr microscopy. From our direct domain observation, it is revealed that, when a negative exposure field has been applied after positively saturating the film first, the number of pre-existing nucleation sites decreases as a strength and an applied time of the exposure field increase. It was also observed that pre-existing nucleation sites can speed up the magnetization reversal process by two orders of magnitude, where a strong correlation between the number of nucleation sites and the half-reversal time is found. [ABSTRACT FROM AUTHOR]