FLOWER STATE MICROMAGNETIC STRUCTURES IN A FINE PARALLELEPIPED AND A FLAT CYLINDER

Flower state micromagnetic structures in a fine ferromagnetic parallelepiped and a rather flat cylinder with an easy axis of magnetocrystalline anisotropy perpendicular to the cylinder axis are studied by means of the perturbation theory given recently in Ref. [1]. The flower state patterns in these particles are also analyzed in detail with the help of a computer simulation. The comparison of the numerical and analytical data obtained for the wide ranges of particle sizes and aspect ratios shows that the lowest-order formulas of the perturbation theory fit quantitatively the flower state patterns in small enough particles with L less-than-or-equal-to 0.3R0, where L is the characteristic length of a particle and R0 is the exchange length. It is found that due to the similar increases in particle size the amplitude of a flower state increases gradually. Nevertheless, there is no qualitative change in the magnetization pattern, so that the numerical and analytical data remain similar up to L congruent-to R0, where the stability of a flower state in a soft-type particle vanishes.