  The magnetization reversal process in thin-film ferromagnetic elements with
surface anisotropy of various shapes and sizes is investigated by means of
numerical simulation. The dependence of the perpendicular and in-plane
hysteresis loops on the element thickness and the value of the surface
anisotropy constant is obtained. For sufficiently large values of the surface
anisotropy constant the magnetization reversal of thin-film elements is shown
to occur due to the nucleation of the buckling mode. For an elongated
rectangular element the nucleation field of the buckling mode is proportional
to the absolute value of the surface anisotropy constant, and inversely
proportional to the element thickness.
