arXiv subjects

V. Vlaminck

Publications and source records attributed to V. Vlaminck.

5 recordsLinked to original sources

arXiv2026

Coupling phase interference effects in a multimode cavity magnonics system

Coupling phases play a decisive yet often overlooked role in cavity magnonics, particularly in complex multimode systems. Here, we investigate phase-mediated interference effects in a cavity magnonics system comprising a four-post re-entrant microwave cavity coupled to Yttrium Iron Garnet (YIG) spheres. Using an input-output model that explicitly accounts for both internal and external coupling phases, we achieve agreement with experimental microwave transmission measurements. Our results unravel the emergence of a positionally-dependent uncoupled mode due to interference of cavity photon-magnon (internal) coupling phases. Further, we experimentally observed large nonreciprocity at the antiresonance frequencies and show that this feature arises due to the far-detuned modes' odd parity cavity photon-probe (external) coupling phase interfering with the internal coupling phases. Bridging theory, simulation and experiment, these results establish coupling-phase engineering as a key principle for accurately modeling and designing multimode cavity magnonics devices.

quant-ph↗

arXiv2023

High wave vector non-reciprocal spin wave beams

We report unidirectional transmission of micron-wide spin waves beams in a 55 nm thin YIG. We downscaled a chiral coupling technique implementing Ni80Fe20 nanowires arrays with different widths and lattice spacing to study the non-reciprocal transmission of exchange spin waves down to lambda = 80 nm. A full spin wave spectroscopy analysis of these high wavevector coupled-modes shows some difficulties to characterize their propagation properties, due to both the non-monotonous field dependence of the coupling efficiency, and also the inhomogeneous stray field from the nanowires.

physics.app-ph↗

arXiv2023

Spin wave diffraction model for perpendicularly magnetized films

We present a near-field diffraction model for spin waves in perpendicularly magnetized films applicable in any geometries of excitation fields. This model relies on Kalinikos-Slavin formalism to express the dynamic susceptibility tensor in k-space, and calculate the diffraction patterns via inverse 2D-Fourier transform of the response functions. We show an excellent quantitative agreement between our model and MuMax3 micro-magnetic simulations on two different geometries of antennas. Our method benchmarks spin wave diffraction in perpendicularly magnetized films, and is readily applicable for future designs of magnon beamforming and interferometric devices.

cond-mat.other↗

arXiv2013

A Universal Method for Separating Spin Pumping from Spin Rectification Voltage of Ferromagnetic Resonance

We develop a method for universally resolving the important issue of separating spin pumping (SP) from spin rectification (SR) signals in bilayer spintronics devices. This method is based on the characteristic distinction of SP and SR, as revealed in their different angular and field symmetries. It applies generally for analyzing charge voltages in bilayers induced by the ferromagnetic resonance (FMR), independent of FMR line shape. Hence, it solves the outstanding problem that device specific microwave properties restrict the universal quantification of the spin Hall angle in bilayer devices via FMR experiments. Furthermore, it paves the way for directly measuring the nonlinear evolution of spin current generated by spin pumping. The spin Hall angle in a Py/Pt bilayer is thereby directly measured as 0.021$\pm$0.015 up to a large precession cone angle of about 20$^{\circ}$.

cond-mat.mtrl-sci↗

arXiv2010

Detection and quantification of inverse spin Hall effect from spin pumping in permalloy/normal metal bilayers

Spin pumping is a mechanism that generates spin currents from ferromagnetic resonance (FMR) over macroscopic interfacial areas, thereby enabling sensitive detection of the inverse spin Hall effect that transforms spin into charge currents in non-magnetic conductors. Here we study the spin-pumping-induced voltages due to the inverse spin Hall effect in permalloy/normal metal bilayers integrated into coplanar waveguides for different normal metals and as a function of angle of the applied magnetic field direction, as well as microwave frequency and power. We find good agreement between experimental data and a theoretical model that includes contributions from anisotropic magnetoresistance (AMR) and inverse spin Hall effect (ISHE). The analysis provides consistent results over a wide range of experimental conditions as long as the precise magnetization trajectory is taken into account. The spin Hall angles for Pt, Pd, Au and Mo were determined with high precision to be $0.013\pm0.002$, $0.0064\pm0.001$, $0.0035\pm0.0003$ and $-0.0005\pm0.0001$, respectively.

cond-mat.other↗