  We demonstrate (using full-scale micromagnetic simulations) that the spin
injection driven steady-state precession of a thin magnetic nanoelement exhibit
a complicate transition from the quasi-macrospin to the chaotic behaviour with
the increasing element size. For nanoelement parameters typical for those used
experimentally we have found that the macrospin approximation becomes invalid
already for very small nanoelement sizes (~ 30 nm), in contrast to the
previously reported results (Li and Zhang, Phys. Rev. B, vol. B68, 024404-1
(2003))
