Spin waves are ideal candidates for wave-based computing, but the construction of magnetic circuits is blocked by a lack of an efficient mechanism to excite long-running exchange spin waves with normalised amplitudes. Here, we solve the challenge by exploiting the deeply nonlinear phenomena of forward-volume spin waves in 200 nm wide nanoscale waveguides and validate our concept with microfocused Brillouin light scattering spectroscopy. An unprecedented nonlinear frequency shift of >2 GHz is achieved, corresponding to a magnetisation precession angle of 55{\deg} and enabling the excitation of exchange spin waves with a wavelength of down to ten nanometres with an efficiency of >80%. The amplitude of the excited spin waves is constant and independent of the input microwave power due to the self-locking nonlinear shift, enabling robust adjustment of the spin wave amplitudes in future on-chip magnonic integrated circuits.
@article{arxiv.2207.01121,
title = {Deeply nonlinear excitation of self-normalised exchange spin waves},
author = {Qi Wang and Roman Verba and Björn Heinz and Michael Schneider and Ondřej Wojewoda and Kristýna Davídková and Khrystyna Levchenko and Carsten Dubs and Norbert J. Mauser and Michal Urbánek and Philipp Pirro and Andrii V. Chumak},
journal= {arXiv preprint arXiv:2207.01121},
year = {2022}
}