Real time dynamics in epitaxial Fe(100) disks

Real time resolved scanning Kerr microscopy has been used to study the swit ching dynamics of 50 mum diameter epitaxial Fe(100) disks. The measurements were performed using a sinusoidal sweeping field with a sweep rate of dH/d t = 10 kOe/s. By performing repetitive one-shot measurements, we have mappe d the statistical fluctuations and the probability distribution of characte ristic switching parameters as the switching instant t(0), and the switchin g speed, V. We observe a substantial difference in the parameters estimated from the average of several measurements compared to the parameters extrac ted from the probability distributions. This illustrates the potential risk s of using averaging techniques in dynamic measurements, in addition to the loss of the statistical information. The disks were found to display an in homogeneous switching, which is believed to be caused by defect damped moti on of the domain walls and a inhomogeneous distribution of defects. (C) 200 1 American Institute of Physics.