The energy and width of paired Neel walls in double layer M-R films

The energy and wall width of paired Neel walls are analytically examined. The walls studied are those which are perpendicular to the easy axes in double-layer MR (magnetoresistive) elements. Specifically, the material examined consisted of two 150-Å-thick magnetic layers separated by 50 Å. The anisotropy constant was assumed to be 20 Oe, the exchange constant 1.25×10^-6 erg/cm, and the saturation magnetization 983 G/4π. Wall energies ranged from 0.03 erg/cm² to 1.8 erg/cm² as the total angle of rotation across the wall varied from 60° to 270°. Wall width ranged from 2.0 μm to 0.5 μm. The wall energies were found to be approximately one eighth of those of single-layer Neel walls. The wall widths were found to vary less with total wall angle than those encountered with a single-layer Neel wall. The paired Neel walls are generally wider than those for a single-layer film