Towards a more analytic understanding of the pinning of domain walls in high-temperature permanent magnets

We discuss analytic results for the depinning of domain walls based on diff erent models for wan pinning in permanent magnets. We propose an explanatio n for the different temperature dependences of the coercive field for repul sive and attractive pinning potential when the pinning boundary forms an ar ray of pyramids and suggest that the switching dynamics are different in th e two regimes. This may be tested experimentally by magnetic viscosity meas urements on samples with different Cu contents. We also found analytically that when the pinning boundary forms an array of cubes, the coercive field always decreases no matter whether the pinning potential is repulsive or at tractive. This is confirmed by Monte Carlo simulations. (C) 2000 Elsevier S cience B.V. All rights reserved.