The effect of magnetic properties on magnetization dynamics is studied for a spin torque oscillator (STO) composed of a free layer with an in-plane magnetic anisotropy and a reference layer with a fixed out-of plane magnetization. A transition from damped to uniform oscillations is observed for a critical value of saturation magnetization M-S). In the uniform oscillations regime, the frequency is inversely proportional to M-S. Similarly, the critical current for achieving uniform oscillations is investigated as a function of free layer intrinsic properties. In a second part of the study, the magnetostatic field (H-m) from the reference layer is considered and it is revealed that the out-of plane component of magnetization has a strong dependence on H-m. For a particular configuration, H-m could reduce the out-of plane component maximizing thus the out-put signal of the STO. (C) 2014 Elsevier E.V. All rights reserved.