  Hysteresis loops of 3D ferromagnetic permalloy nano-half-balls (dots) with
100 nm base diameter have been examined by means of LLG micromagnetic
simulations and finite element methods. Tests were carried out with two
orthogonal directions of the externally applied field at 10 kA/(m.ns) field
sweeping speed. The comparison of samples with different 3D modifications at
the sub-10nm scale, accessible by nowadays lithographic techniques, enables
conclusions about different mechanisms of competition between demagnetizing and
exchange fields. Design paradigms provided here can find possible applications
in magneto-electronic devices.
