We report on a novel dynamical phenomenon in electron spin resonance experiments of phosphorus donors. When strongly coupling the paramagnetic ensemble to a superconducting lumped element resonator, the coherent exchange between these two subsystems leads to a train of periodic, self-stimulated echos after a conventional Hahn echo pulse sequence. The presence of these multi-echo signatures is explained using a simple model based on spins rotating on the Bloch sphere, backed up by numerical calculations using the inhomogeneous Tavis-Cummings Hamiltonian.
@article{arxiv.1809.10116,
title = {Echo trains in pulsed electron spin resonance of a strongly coupled spin ensemble},
author = {Stefan Weichselbaumer and Matthias Zens and Christoph W. Zollitsch and Martin S. Brandt and Stefan Rotter and Rudolf Gross and Hans Huebl},
journal= {arXiv preprint arXiv:1809.10116},
year = {2020}
}