B. Hillebrands et al., STATIC AND DYNAMIC PROPERTIES OF PATTERNED MAGNETIC PERMALLOY-FILMS, Journal of magnetism and magnetic materials, 175(1-2), 1997, pp. 10-15
Static magnetic and spin-wave properties of square lattices of permall
oy micron dots with thicknesses of 500 Angstrom and 1000 Angstrom and
with varying dot separations have been investigated. The spin-wave fre
quencies can be well described taking into account the demagnetization
factor of each single dot. A magnetic fourfold anisotropy was found f
or the lattice with dot diameters of 1 mu m and a dot separation of 0.
1 mu m. The anisotropy is attributed to an anisotropic dipole-dipole i
nteraction between magnetically unsaturated parts of the dots. The ani
sotropy strength (order of 10(5) erg/cm(3)) decreases with increasing
in-plane applied magnetic field.