An array of spin torque nano-oscillators (STNOs), coupled by dipolar interaction and arranged on a ring, has been studied numerically and analytically. The phase patterns and locking ranges are extracted as a function of the number N, their separation, and the current density mismatch between selected subgroups of STNOs. If N≥6 for identical current densities through all STNOs, two degenerated modes are identified an in-phase mode (all STNOs have the same phase) and an out-of-phase mode (the phase makes a 2π turn along the ring). When inducing a current density mismatch between two subgroups, additional phase shifts occur. The locking range (maximum current density mismatch) of the in-phase mode is larger than the one for the out-of-phase mode and depends on the number N of STNOs on the ring as well as on the separation. These results can be used for the development of magnetic devices that are based on STNO arrays.
@article{arxiv.2108.04046,
title = {Mutual Synchronization of Spin-Torque Oscillators within a Ring Array},
author = {M. A. Castro and D. Mancilla-Almonacid and B. Dieny and S. Allende and L. D. Buda-Prejbeanu and U. Ebels},
journal= {arXiv preprint arXiv:2108.04046},
year = {2021}
}