Delft University of Technology

Spin waves are collective excitations of the spins in magnetic materials. They play an important role in
the thermodynamics of magnetic materials and are promising as signal carriers in information devices.
In this talk, I will introduce magnetic imaging based on electron spins in diamond and boron nitride(1,
2) as a microscopy technique for studying spins and electric currents in materials on the micro-tonanoscale.
I will show how this technique enables imaging spin waves in thin magnetic films and
describe experiments on the interaction of spin waves with currents in normal3 and superconducting
metals(3). Our results indicate that superconductors provide opportunities for realizing tunable spinwave
optical devices that could be used for on-chip microwave-control in classical or quantum circuits.

1. F. Casola, T. Van Der Sar, A. Yacoby, Probing condensed matter physics with
magnetometry based on nitrogen-vacancy centres in diamond. Nat Rev Mater. 3
(2018), doi:10.1038/natrevmats.2017.88.
2. I. Bertelli et al., Magnetic resonance imaging of spin-wave transport and interference
in a magnetic insulator. Sci Adv. 6, eabd3556 (2020).
3. M. Borst et al., Observation and control of hybrid spin-wave–Meissner-current