  In this paper we numerically conduct micromagnetic modelling with an expended
micromagnetic model that includes the spin torque term and an impedance model
to investigate methods to replace external field sources with internal ones and
to investigate its tuneability on nanopillar geometries. We present results for
three methods: interlayer coupling, large perpendicular anisotropy and
magnetostatic coupling. The internal field sources are evaluated as function of
frequency shift with current, its dependency on temperature and are tested
against analytical predictions.
