A Model for the Interaction of Magnetic Domain Walls with Crystalline Imperfections

Abstract

The interaction of a domain wall with a crystalline defect is frequently represented by means of a potential-energy function which gives the energy of the wall as a function of position. However, it was shown ten years ago by Rodbell and Bean that the experimental dependence of wall velocity on applied magnetic field is inconsistent with the predictions of a theory in which the interaction of a wall with a defect is taken to be conservative. In the present paper a model is proposed in which this interaction is mainly nonconservative. It is shown that this model is in agreement with wall-velocity measurements. It also predicts the reversible spikes found on the leading and trailing edges of the switching voltage when a pulse of magnetic field is applied to a square-loop sample. Finally, it is shown that the model predicts a Rayleigh hysteresis loop. A one-parameter expression is given for the Rayleigh loop of a single-crystal window frame.