Via a direct coupling between the magnetic order parameter and the singlet Josephson supercurrent, we detect spin-wave resonances, and their dispersion, in ferromagnetic Josephson junctions in which the usual insulating or metallic barrier is replaced with a weak ferromagnet. The coupling arises within the Fraunhofer interferential description of the Josephson effect, because the magnetic layer acts as a time dependent phase plate. A spin-wave resonance at a frequency ws implies a dissipation that is reflected as a depression in the current-voltage curve of the Josephson junction when hbar ws = 2eV. We have thereby performed a resonance experiment on only 10^7 Ni atoms.
@article{arxiv.0904.1780,
title = {Coupled Superconducting Phase and Ferromagnetic Order Parameter Dynamics},
author = {I. Petkovic and M. Aprili and S. E. Barnes and F. Beuneu and S. Maekawa},
journal= {arXiv preprint arXiv:0904.1780},
year = {2013}
}