On October 30^th, we have the pleasure to welcome in SPINTEC Pim Vree from Delft. He will give us a seminar at 15:30 entitled : Imaging temperature-tunable spin-wave refraction using spins in diamond

Place : IRIG/SPINTEC, room 447 CEA Building 10.05

Abstract : Spin waves, collective excitations of magnetization, are emerging as nanoscale information carriers for magnonic and hybrid quantum technologies. Realizing spin-wave-based devices requires precise control over their propagation. Superconductors provide a tunable means of modifying the spin-wave dispersion through their temperature- and current-dependent electromagnetic response. Through the Meissner effect, superconductors screen the magnetic stray fields generated by spin waves, producing screening currents that couple back to the magnetic system and modify the dispersion relation [1].

In this talk, I will present our results on imaging magnetic stray fields in hybrid yttrium iron garnet (YIG)-superconductor structures. Using diamond membranes hosting nitrogen-vacancy (NV) centers, we map the standing microwave magnetic field arising from the interference between spin waves and a reference field. From these measurements, we extract key parameters of the hybrid system, including the modified spin-wave dispersion and the London penetration depth [2]. Building on this approach, we demonstrate control over spin-wave propagation by orienting the superconducting layer at an angle to the propagation direction, thereby realizing temperature-tunable spin-wave refraction [3].

Our work highlights NV-based magnetometry as a versatile tool for studying and controlling spin-wave transport in hybrid superconducting-magnetic systems.

1. T. Yu and G. E. W. Bauer, Efficient gating of magnons by proximity superconductors, Phys. Rev. Lett. 129, 117201 (2022).
2. M. Borst, P. H. Vree, A. Lowther, A. Teepe, S. Kurdi, I. Bertelli, B. G. Simon, Y. M. Blanter, and T. van der Sar, Observation and control of hybrid spin-wave-Meissner-current transport modes, Science 382, 430-434 (2023).
3. P. H. Vree, M. A. Bouma, M. Borst, T. T. Osterholt, R. A. Duine, and T. van der Sar, Temperature-tunable spin-wave refraction using superconducting control elements, arXiv:2608.06555 (2026).