Other Condensed Matter

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Cross submissions (showing 1 of 1 entries)

[1] arXiv:2411.13414 (cross-list from cond-mat.mes-hall) [pdf, html, other]

Title: Wavenumber-dependent magnetic losses in YIG-GGG heterostructures at millikelvin temperatures

David Schmoll, Andrey A. Voronov, Rostslav O. Serha, Denys Slobodianiuk, Khrystyna O. Levchenko, Claas Abert, Sebastian Knauer, Dieter Suess, Roman Verba, Andrii V. Chumak

Comments: 9 pages, 4 figures

Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Materials Science (cond-mat.mtrl-sci); Other Condensed Matter (cond-mat.other)

Magnons have inspired potential applications in modern quantum technologies and hybrid quantum systems due to their intrinsic nonlinearity, nanoscale scalability, and a unique set of experimentally accessible parameters for manipulating their dispersion. Such magnon-based quantum technologies demand long decoherence times, millikelvin temperatures, and minimal dissipation. Due to its low magnetic damping, the ferrimagnet yttrium iron garnet (YIG), grown on gadolinium gallium garnet (GGG), is the most promising material for this objective. To comprehend the magnetic losses of propagating magnons in such YIG-GGG heterostructures at cryogenic temperatures, we investigate magnon transport in a micrometer-thick YIG sample via propagating spin-wave spectroscopy (PSWS) measurements for temperatures between 4K to 26mK. We demonstrate an increase in the dissipation rate with wavenumber at cryogenic temperatures, caused by dipolar coupling to the partially magnetized GGG substrate. Additionally, we observe a temperature-dependent decrease in spin-wave transmission, attributed to rare earth ion relaxations. The critical role of the additional dissipation channels at cryogenic temperatures is underpinned by the comparison of the experimental results with theoretical calculations and micromagnetic simulations. Our findings strengthen the understanding of magnon losses at millikelvin temperatures, which is essential for the future detection of individual propagating magnons.

Replacement submissions (showing 1 of 1 entries)

[2] arXiv:2407.09411 (replaced) [pdf, html, other]

Title: Ambiguous Resonances in Multipulse Quantum Sensing with Nitrogen Vacancy Centers

Lucas Tsunaki, Anmol Singh, Kseniia Volkova, Sergei Trofimov, Tommaso Pregnolato, Tim Schröder, Boris Naydenov

Comments: 14 pages, 8 figures, for associated dataset, see this https URL

Subjects: Quantum Physics (quant-ph); Other Condensed Matter (cond-mat.other)

Dynamical decoupling multipulse sequences can be applied to solid state spins for sensing weak oscillating fields from nearby single nuclear spins. By periodically reversing the probing system's evolution, other noises are counteracted and filtered out over the total evolution. However, the technique is subject to intricate interactions resulting in additional resonant responses, which can be misinterpreted with the actual signal intended to be measured. We experimentally characterized three of these effects present in single nitrogen vacancy centers in diamond, where we also developed a numerical simulations model without rotating wave approximation, showing robust correlation to the experimental data. Regarding centers with the $^{15}$N nitrogen isotope, we observed that a small misalignment in the bias magnetic field causes the precession of the nitrogen nuclear spin to be sensed by the electronic spin of the center. Another studied case of ambiguous resonances comes from the coupling with lattice $^{13}$C nuclei, where we used the echo modulation frequencies to obtain the interaction Hamiltonian and then utilized the latter to simulate multipulse sequences. Finally, we also measured and simulated the effects from the free evolution of the quantum system during finite pulse durations. Due to the large data volume and the strong dependency of these ambiguous resonances with specific experimental parameters, we provide a simulations dataset with a user-friendly graphical interface, where users can compare simulations with their own experimental data for spectral disambiguation. Although focused with nitrogen vacancy centers and dynamical decoupling sequences, these results and the developed model can potentially be applied to other solid state spins and quantum sensing techniques.