We study the magnetization dynamics of spin valve structures with a free composite synthetic ferromagnet (SyF) that consists of two ferromagnetic layers coupled through a normal metal spacer. A ferromagnetically coupled SyF can be excited into dynamical precessional states by an applied current without external magnetic fields. We analytically determine the stability of these states in the space spanned by the current density and SyF interlayer exchange coupling. Numerical simulations confirm our analytical results.
@article{arxiv.1301.4294,
title = {Field-Free Synthetic-Ferromagnet Spin Torque Oscillator},
author = {Yan Zhou and Jiang Xiao and Gerrit E. W. Bauer and F. C. Zhang},
journal= {arXiv preprint arXiv:1301.4294},
year = {2013}
}