Neel wall

The N´eel wall, where the magnetization rotates within the plane of the domain magnetization, is normally higher in energy than the Bloch wall because of the stray field created by the nonzero divergence of M. But unlike the Bloch wall, the N´eel wall creates no surface charge, and there is no associated stray field. N´eel lines are actually strips of N´eel wall. When two regions of N´eel wall with opposite chirality meet, there forms a strip of Bloch wall, which we call a Bloch line.

N´eel walls are only stable in films thinner than the wall width. To explain the formation of hiswallsN´eel represented thewall by an elliptical cylinder of cross section t × δ where t is the film thickness. For a bulk sample the demagnetizing factor for the Blochwall is zero,while that for theN´eelwall is 1. When t < δ the N´eel wall has the lower magnetostatic energy. However, the Bloch wall width itself is much reduced in thin films in order to minimize the stray field. The Bloch–N´eel crossover thickness in a film of permalloy (Ni₈₀Fe₂₀) is at 60 nm.

A cross-tie wall is a N´eel wall in which the magnetization rotates in opposite directions in adjacent sections. Transitions between domains in thicker films may have vortex structures, mixtures with N´eel caps at the surface and Bloch character at the centre. There is rich fauna in the micromagnetic jungle.

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