Head to head domain wall structures in thin magnetic strips

We present calculations of head to head domain wall structures in magnetic strips of Ni/sub 80/Fe/sub 20/ with widths, w, ranging from 75 nm to 500 nm and thicknesses, t, from 1 nm to 64 nm. Neglecting magnetocrystalline and magnetostrictive anisotropy energies, minimization of exchange and magnetostatic energy leads to one of two types of domain wall structures: 'transverse' walls with magnetization at the center of the wall directed transverse to the strip axis and 'vortex' walls where the magnetization forms a vortex at the center of the wall. Calculation of the domain wall energies leads to a proposed phase diagram for head to head domain walls where transverse walls have lower energy when dimensions are less than t/sub crit/w/sub crit//spl ap/130 A//spl mu//sub 0/M/sub s//sup 2/.