We have measured spin transfer-induced dynamics in magnetic nanocontact devices having a perpendicularly magnetized Co/Ni free layer and an in-plane magnetized CoFe fixed layer. The frequencies and powers of the excitations agree well with the predictions of the single-domain model and indicate that the excited dynamics correspond to precessional orbits with angles ranging from zero to 90 degrees as the applied current is increased at a fixed field. From measurements of the onset current as a function of applied field strength we estimate the magnitude of the spin torque asymmetry parameter lambda ~ 1.5. By combining these with spin torque ferromagnetic resonance measurements, we also estimate the spin wave radiation loss in these devices.
@article{arxiv.0911.4077,
title = {Spin Transfer Dynamics in Spin Valves with Out-of-plane Magnetized CoNi Free Layers},
author = {William H. Rippard and Alina M. Deac and Matthew R. Pufall and Justin M. Shaw and Mark W. Keller and Stephen E. Russek and Gerrit E. W. Bauer and Claudio Serpico},
journal= {arXiv preprint arXiv:0911.4077},
year = {2015}
}