4 research outputs found
Interplay between magnetism and superconductivity in a hybrid magnon photon bilayer system
No full textSpin waves in magnetic films are affected by the vicinity to a superconductor. Here we focus on a bilayer stack made of an insulating yttrium iron garnet (YIG) film and a high-tcYBa2Cu3O7 (YBCO) superconducting planar resonator and report microwave transmission spectra to monitor the temperature evolution of magnon-photon polaritons. We show that the observed temperature dependence of normal-mode splitting and frequency shift with respect to the unperturbed magnon mode can be ultimately related to the penetration depth of YBCO, as an effect of the interplay between spin waves and Meissner currents
Coupling Sub-nanoliter BDPA Organic Radical Spin Ensembles with YBCO Inverse Anapole Resonators
No full textWe report the development and test of planar microwave Inverse Anapole Resonators (IARs) made of superconducting Yttrium Barium Copper Oxide (YBCO) for electron spin resonance spectroscopy on small samples. We first characterize our resonators in zero field and then by carrying out transmission spectroscopy on a diluted α,γ-bisdiphenylene-β-phenylally (BDPA) organic radical spin ensemble in an applied magnetic field. These IARs allow us to carry out electron spin resonance spectroscopy both in continuous-wave and pulsed-wave mode, and to estimate the spin memory time of BDPA. The comparison with the results obtained for the same sample on typical linear coplanar resonators shows an improvement by ≈2 - up to3 – orders of magnitude in spin sensitivity, with effective sensing volumes below 1 nanoliter. The best sensitivity we achieved is S≈10^7 spin/(Hz)^1/2 in the pulsed-wave regime. These results compare well with similar experiments reported in the literature
Interplay between magnetism and superconductivity in a hybrid magnon-photon bilayer system
No full textSpin waves in magnetic films are affected by the vicinity to a superconductor. Here we focus on a bilayer stack made of an insulating Yttrium Iron Garnet (YIG) film and a high- YBCO superconducting planar resonator and report microwave transmission spectra to monitor the temperature evolution of magnon-photon polaritons. We show that the observed temperature dependence of normal mode splitting and frequency shift with respect to the unperturbed magnon mode can be ultimately related to the penetration depth of YBCO, as an effect of the interplay between spin waves and Meissner currents
Ultrastrong Magnon-Photon Coupling Achieved by Magnetic Films in Contact with Superconducting Resonators
No full textCoherent coupling between spin wave excitations (magnons) and microwave
photons in a cavity may disclose new paths to unconventional phenomena as well
as for novel applications. Here, we present a systematic investigation on YIG
(Yttrium Iron Garnet) films on top of coplanar waveguide resonators made of
superconducting YBCO. We first show that spin wave excitations with frequency
higher than the Kittel mode can be excited by putting in direct contact a
5~m thick YIG film with the YBCO coplanar resonator (cavity frequency
~GHz). With this configuration, we obtain very large
values of the collective coupling strength ~GHz and
cooperativity . Transmission spectra are analyzed by a
modified Hopfield model for which we provide an exact solution that allows us
to well reproduce spectra by introducing a limited number of free parameters.
It turns out that the coupling of the dominant magnon mode with photons exceeds
0.2 times the cavity frequency, thus demonstrating the achievement of the
ultrastrong coupling regime with this architecture. Our analysis also shows a
vanishing contribution of the diamagnetic term which is a peculiarity of pure
spin systems
