Coercivity spectrum and domain wall creep in 200 to 1000 Å permalloy films

Abstract

Investigations of cross‐tie wall deformation under the influence of magnetic field carried out by magnetic suspension have revealed the nonuniform interaction of wall elements with the magnetic film potential relief. The Néel segment coercive field HcN is the less (HcN ≈︁ 0.1 Oe) and that may be explained by the theory of ripple induced coercivity. The cross‐tie coercive field Hct changes with film thickness within the limits of 0.3 to 0.7 Oe (under stray field influence) and reaches its minimum at d ≈︁ 600 Å. Following a decrease in field Hct with thickness the creep kinematics varies due to changes in the effective distance between the wall points fixed at defects. The maximum creep efficiency is shown to be connected not with the greatest cross‐tie density but with the growth of the distance le. The macroscopic coercive field of domain wall motion Hst≈︁1.0 Oe is defined by the nature of separate large imperfections.