Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session B57: Magnonics IFocus
|
Hide Abstracts |
Sponsoring Units: GMAG Chair: Jiaming He, University of Texas at Austin Room: Room 303 |
Monday, March 6, 2023 11:30AM - 12:06PM |
B57.00001: Giovanni Vignale - Atomically sharp domain walls as antiferromagnetic spin wave polarizers Invited Speaker: Giovanni Vignale We present theoretical evidence that atomically sharp domain walls in antiferromagnetic materials (i.e., domain walls in which the antiferromagnetic order parameter changes sign abruptly across an atomic layer) have qualitatively different properties from their smooth counterparts, in which the reversal of the antiferromagnetic order parameter occurs gradually over many unit cells. A remarkable difference appears when we consider the effect of the domain wall on the propagation of an antiferromagnetic spin wave. Antiferromagnetic spin waves, unlike ferromagnetic ones, come in two possible states of circular polarization, left handed and right handed. While a smooth domain wall does not distinguish between the two cases, allowing both types of waves to be transmitted with 100% probability (and their polarizations to be reversed in the process), an atomically sharp domain wall acts as a spin wave polarizer, i.e., it allows one type of polarization to be partially transmitted while the other is almost completely reflected. The polarization of the transmitted spin wave depends on the orientation of the spins in the sharp domain wall - a property which can be controlled by an external field or spin torque and has no counterpart in a smooth domain wall. Our discovery of the spin-wave polarizing properties of sharp antiferromagnetic domain walls suggests that they could be used as spin polarizers in magnonic circuits. |
Monday, March 6, 2023 12:06PM - 12:18PM |
B57.00002: Time-Resolved Brillouin Light Scattering measurement of a 1D YIG magnonic crystal Mitchell Swyt, Lia Compton, Cesar L Ordonez Romero, H. J. Jason Liu, Kristen S Buchanan Magnonic crystals are created by introducing a periodic modulation of the material properties that leads to the formation of bands of allowed frequencies where spin waves can pass through the crystal and band gaps where propagation is suppressed. Analogous to photonic crystals in optical devices, magnonic crystals show promise for signal processing and logic applications. Here we report time-resolve Brillouin light scattering (TR-BLS) measurements of a 1D yttrium iron garnet (YIG) magnonic crystal. We have used TR-BLS in the surface wave geometry to observe 200-ns long spin wave pulses with frequencies of 4 to 5 GHz propagating through the magnonic crystal. Microwave measurements confirm that periodic grooves etched into the YIG film create band gaps that suppress the transmission of spin waves by >15 dB, and these band gaps are directly observed in the TR-BLS measurements. The TR-BLS measurements provide direct insight into the temporal and spatial evolution of the propagating spin wave packet as it travels through the magnonic crystal, and the differences in the pulse propagation at frequencies within the pass band and within the band gaps will be discussed. |
Monday, March 6, 2023 12:18PM - 12:30PM |
B57.00003: Reconfigurable Spin-wave Dispersion in Continuous Magnetic Layer Induced via Artificial Spin Ice Magnonic Crystal Troy Dion, Will R Branford, Hidekazu Kureyabashi, Takashi Kimura, Jack C Gartside, Daan M Arroo, Alexander L Vanstone, Kilian D Stenning Spinwaves are proposed as next generation information carriers to supersede transistor based computing technologies which are approaching fundamental physical limitations. Spinwave dispersions can be tuned by spatially modulating the properties of the materials through which they propagate, so-called magnonic crystals [1]. Flexible functionality via reconfigurability is a desirable property. Artificial spin ice (ASI) is an arrangement of magnetic nanoislands already showing promise for reservoir computing [2]. Spinwave propagation in nanostructures is inefficient due to dipole-coupling. Iacocca et al. demonstrate increased interisland coupling via a continuous magnetic underlayer [3]. Similarly, we propose ASI as a magnetization modulator of an efficient spinwave supporting media. Using different microstate and underlayer magnetisation directions we demonstrate band gaps, spin-wave non-reciprocity, important for spin-wave diode realisation, and spinwave propagation suppression. Nonreciprocity can be further enhanced by differential fabrication of nano island geometry which also allows access to all microstates with simple fields protocols. |
Monday, March 6, 2023 12:30PM - 12:42PM |
B57.00004: Nonlinear multi-magnon scattering in artificial spin ice Sergi Lendinez, Mojtaba Taghipour Kaffash, Olle Heinonen, Sebastian Gliga, Ezio Iacocca, M. Benjamin Jungfleisch Magnons, the quanta of spin waves, are bosons whose number does not need to be conserved in scattering processes. Microwave-induced parametric magnon processes, often referred to as Suhl instabilities, have been known to occur in magnetic thin films only, where quasi-continuous magnon bands exist. Here, we reveal the existence of such nonlinear magnon-magnon scattering processes and their coherence in ensembles of magnetic nanostructures known as artificial spin ice [1]. These systems show scattering processes akin to those observed in continuous magnetic thin films. We utilize a combined microwave and microfocused Brillouin light scattering measurement approach to investigate the evolution of their modes. Scattering events occur between discrete bands whose resonant frequencies are determined by each nanomagnet's mode volume and profile. Comparison with numerical simulations reveals that parametric pumping leads to scattering from bulk modes into edge modes. Furthermore, our results suggest that tunable directional scattering is possible in these structures. |
Monday, March 6, 2023 12:42PM - 12:54PM |
B57.00005: Topological magnons Se Kwon Kim Topological magnons have emerged as a new research area in magnetism and spintronics due to their fundamental interest as well as practical utilities such as back-scattering-free spin-transport channels. In this talk, we will give a pedagogical introduction to various topological phases of magnons and their closely related cousins with a focus on recently discovered two-dimensional (2D) magnets. We will begin by discussing one of the first magnonic topological insulators realized in a honeycomb 2D ferromagnet such as CrI3, which is shown to give rise to the thermal Hall effect via the finite Berry curvature of magnons [1]. Novel ways to manipulate the topological property of magnons in mono- and bilayer 2D magnets [2-4], which is crucial for the practical application of topological magnons in spintronic devices, will be introduced as well. Recently, the field of topological magnons has been expanded into the field of topological bosons beyond simple magnons. As one concrete example, we will introduce a new concept of topologically non-trivial magnon-phonon hybridized mode called a topological magnon-polaron, which can be realized in a 2D ferromagnet [5,6] and antiferromagnet such as MnPS3 [7] via generic magnetoelastic coupling. The topology of magnon-polarons of antiferromagnets differs from the ferromagnetic counterpart in that the former and the latter concern the SU(3) and the SU(2) topology of quasiparticle bands, respectively, showing the richness of the topological physics of magnon-polarons in magnetic systems. The talk will be concluded with a future outlook on the research of topological magnons and beyond. |
Monday, March 6, 2023 12:54PM - 1:06PM |
B57.00006: Tunable topology of magnon-polarons in two-dimensional magnets Gyungchoon Go, Se Kwon Kim In this talk, I will describe topological transports of magnon-phonon hybrid excitations in two-dimensional magnetic systems. The magnetoelastic interaction opens band gaps and allows the interband transition between different excitation states which leads to the topological transports of the magnon-polarons and their spin angular momenta. In the ferromagnets with broken time-reversal symmetry, the magnon-polaron bands possess nontrivial topology represented by the Chern numbers. In the antiferromagnets in the presence of the time-reversal symmetry, the magnon-polaron bands show the finite spin Berry curvature with vanishing Berry curvature. I will explain how the magnetoelastic interaction leads to the large spin Berry curvature and the large spin Nernst conductivity in the antiferromagnetic systems. |
Monday, March 6, 2023 1:06PM - 1:18PM |
B57.00007: Phase transition in magnon bands in a honeycomb ferromagnet driven by sublattice symmetry breaking Hongseok Kim, Se Kwon Kim Ferromagnetic honeycomb systems are known to exhibit a magnonic topological phase under the existence |
Monday, March 6, 2023 1:18PM - 1:30PM |
B57.00008: Spin wavepackets in the Kagome ferromagnet Fe3Sn2: propagation and precursors Changmin Lee, Yue Sun, Linda Ye, Sumedh Rathi, Joseph G Checkelsky, Joseph W Orenstein The propagation of spin waves in magnetically ordered systems has emerged as a potential means to shuttle quantum information over large distances. Conventionally, the arrival time of a spin wavepacket at a distance, d, is assumed to be determined by its group velocity, vg. He we report time-resolved optical measurements of wavepacket propagation in the Kagome ferromagnet Fe3Sn2 that demonstrate the arrival of spin information at times significantly less than d/vg. We show that this spin wave "precursor" originates from the interaction of light with the unusual spectrum of magnetostatic modes in Fe3Sn2. Related effects may have far-reaching consequences toward realizing long-range, ultrafast spin wave transport in both ferromagnetic and antiferromagnetic systems. |
Monday, March 6, 2023 1:30PM - 1:42PM |
B57.00009: Anisotropic propagation and topological transition of dipolar magnons in biaxial antiferromagnets Yue Sun, Kevin Wang, Yuan-Ming Lu, Joel E Moore, Joseph W Orenstein Coherent magnon transport is an efficient strategy to propagate spin information in spintronics and has been demonstrated to couple with superconducting qubits as a promising candidate of quantum transducer in hybrid quantum system. Among various magnets, antiferromagnets (AFMs) stand at the frontier of magnon transport, since AFMs can host magnons in terahertz frequency and is robust against external field. A recent measurement on 2D A-type AFM CrSBr shows a coherent magnon propagation beyond seven micrometers and nanosecond scale coherence time, but the magnon group velocity is anomalously large comparing to the prediction of linear spin wave theory [1], so that the mechanism of the magnon propagation remains an open question. Here, we demonstrate the magnetic dipole-dipole interaction plays an important role in the AFM magnon dispersion in the long-wavelength limit, known as the dipolar magnon. The dipolar magnon dispersion in a biaxial antiferromagnet matches perfectly with the anisotropic magnon propagation in CrSBr and quantitatively reproduces the group velocity. Furthermore, a topological transition of magnon bands is found in biaxial antiferromagnets by applying a magnetic field perpendicular to the easy axis. A symmetry-protected surface state is shown to propagate without back-scattering along the sample boundary, which opens the new possibility of dissipationless magnon transport. |
Monday, March 6, 2023 1:42PM - 1:54PM |
B57.00010: Reinforcing spin wave non-reciprocity via multiple mechanisms Jinho Lim, Axel Hoffmann, Robin Klause We have studied spin wave propagation in exchange biased ferromagnet (FM) / antiferromagnet (AFM) bilayer systems with the Damon-Eshbach (DE) geometry which corresponds to n⊥M, n⊥k, and M⊥k where n is the film normal, k is the wavevector, and M is the magnetization. Due to pinned spins in the presence of the interlayer exchange interaction at FM / AFM interface, surface spin waves propagating along the FM / AFM interface were suppressed, resulting in spin wave non-reciprocity. Furthermore, we have shown that Oersted field from a patterned coplanar waveguide (CPW) on the film, in all possible four configurations (CPW above or below the FM / AFM bilayer or forward or reversed M), was always coupled strongly with a surface spin wave propagating on the opposite surface. Therefore, we have found that the CPW needs to be patterned on top of the AFM layer (FM / AFM / CPW) to make a geometry where different mechanisms for nonreciprocity ‘interfere constructively’. By using these two mechanisms at the same time, we have achieved enhanced nonreciprocity bigger than those achieved from either of single mechanism. We also found that in a ‘destructively interfering’ geometry nonreciprocity was smaller than those from either of the single mechanisms. |
Monday, March 6, 2023 1:54PM - 2:06PM |
B57.00011: Investigating voltage-control of magnon spin transport in room-temperature multiferroic Sr3Co2Fe24O41 using nonlocal device-geometry Aditya A Wagh, Priyanka Garg, Shwetha G Bhat, Krishna Jha, Suja Elizabeth, P S Anil Kumar Spintronic devices based on pure magnon spin currents are envisaged as next-generation efficient devices due to absence of Joule heating. Besides, voltage control of the magnon transport has recently attracted great attention from the spintronics community [1]. In this regard, room-temperature magnetoelectric multiferroic Sr3Co2Fe24O41 (SCFO) is a promising material for studying voltage-controlled nonlocal magnon transport. Notably, our earlier spin transport studies on bulk SCFO showed that spin pumping and spin current absorption by the SCFO|Pt interface can be tuned by manipulating the conical magnetic structure of SCFO [2]. |
Monday, March 6, 2023 2:06PM - 2:18PM Author not Attending |
B57.00012: µ-BLS characterization of reconfigurable voltage-controlled magnonics crystal at the sub-micron scale Ping Che, Isabella Boventer, Jean-Paul Adam, Sali Salama, Aya El Kanj, Lucía Iglesias, Vincent Garcia, Stéphane Fusil, Agnès Barthélémy, Manuel Bibes, Paolo Bortolotti, Abdelmadjid Anane Magnonics is receiving considerable attention as it promises miniaturized low-power-consuming information technologies thanks to the spin wave precession with only momentum transmission without moving charges and the nanoscale wavelength of spin waves at giga-hertz frequencies. Magnonic crystals provide the ability to engineer magnon band structures with bandgaps and establish magnon channels via the periodic modulation of the internal field, offering more flexibility for miniaturized magnonic devices application. Reconfigurability is key to magnonics devices to achieve multiple functions such as frequency filtering. However, at the sub-micron scale, magnonics crystals are mostly achieved by bottom-up nanofabrication and challenging to reprogram as the patterning is unalterable. Here, we create a reprogrammable magnonics crystal by combining ferromagnets with multiferroics which is capable of implementing voltage-control. The magnonic crystal was constructed in a thin-film multiferroic bismuth ferrite BiFeO3 (BFO)- lanthanum strontium manganite La2/3Sr1/3MnO3 (LSMO) heterostructure by imprinting a periodic remnant electrical polarization in the multiferroic BFO layer which modulates the effective magnetic field seen by the magons in the LSMO layer. We characterize the spin wave propagation spectra in this artificial, voltage-induced magnonic crystal and demonstrate using µ-BLS the occurrence of a robust magnonic bandgap indicating a filtering effect. The imprinted ferroelectric domains can be reconfigured repeatedly and are robust. Our results open a new path for the function of transduction and reconfigurable filtering of spin waves by CMOS compatible voltage control. In general, by bridging between the scientific fields of functional oxides and magnonics, we propose new perspectives for the development of beyond CMOS based technologies. |
Monday, March 6, 2023 2:18PM - 2:30PM |
B57.00013: Magnon heat transport in an antiferromagnetic insulator Ehsan Faridi, Se Kwon Kim, Giovanni Vignale We theoretically investigate the magnon heat transport in an antiferromagnetic (AFM) insulator containing an atomically sharp domain wall (DW) in the presence of a magnetic field. It has been known that, while in the continuum approximation and in the absence of a magnetic field a spin wave is able to pass through a DW without reflection, a narrow DW gives rise to finite reflection coefficients which modify the magnon heat transport [1]. In this work, we investigate the effect of an external field on the magnon heat transport in the presence of a sharp domain wall. Specifically, we find that applying a magnetic field lifts the degeneracy between two AFM magnon modes of opposite polarizations. This results in different occupation numbers for the two magnon modes, which along with the finite reflection coefficients is found to have a significant impact on the magnon heat transport, offering a way to realize a tunable heat transport in an AFM DW. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700