  A system consisting of a point material particle and a scalar field described
by the nonlinear Klein-Gordon equation has been considered. It has been shown
that, when taking into account relativistic effects, in the case of small rest
masses of a particle an energy minimum at zero velocity is impossible for such
a particle. It has been proved that under certain parameters the spin state of
a particle has a lower energy than its steady state does. Such a behavior is
interesting for the construction of soliton models of spin. By a point particle
spin an intrinsic angular momentum (orbital, in strict sense, but with a short
orbital radius) of a point particle is meant.
