Abstract Strain provides an energy-efficient route to reconfiguring magnonic functionalities, yet the physical mechanisms by which strain reshapes spin-wave spectra in magnonic crystals supported on deformable substrates remain insufficiently understood. Here, we investigate how the elastic modulus of the substrate governs strain-induced modifications of magnonic band structures in two-dimensional arrays of CoFeB nanomagnets, using a numerical multiphysics approach that couples magnetization dynamics with solid mechanics. We show that substrates with higher elastic modulus transmit a finite strain into the nanomagnets, giving rise to strong magnetoelastic fields that dominate the band evolution, whereas highly compliant substrates accommodate most of the applied strain within the substrate itself, concentrating strain between elements and primarily modifying dipolar interactions. As a result, for identical applied strains, substrates such as PDMS and Kapton lead to qualitatively different magnonic band structures due to their strongly contrasted strain-transfer characteristics. These findings establish substrate elasticity as a key design parameter for engineering strain-tunable and mechanically reconfigurable magnonic crystals.
The ever-increasing demand for fast, reliable, and energy-efficient information storage continues to push magnetic memory technologies toward their fundamental limits. Conventional scaling strategies, which rely on reducing bit size, inevitably run into the “magnetic recording trilemma,” where signal-to-noise ratio, thermal stability, and writability cannot all be optimized simultaneously. Heat-assisted magnetic recording (HAMR) has emerged as the leading solution, enabling high-density storage by transiently heating the medium during the write cycle. However, the reliance on laser optics and plasmonic transducers restricts HAMR primarily to hard-disk drives, limiting its integration with on-chip or embedded architectures. Here, we demonstrate an electronic variant of HAMR in which Joule heating from low-current density current pulses facilitates data writing, while the anomalous Hall effect provides electronic readout. Employing intercalated 2D magnet Ni1/4TaSe2, we show direct evidence that current pulses heat the material above its Curie temperature, during which a small magnetic field of 2 mT(100 times smaller than the coercive field) enables efficient data writing. The all-electronic approach combined with the 2D magnetic medium creates timely opportunities to revisit the energy-assisted magnetization recording, enabling new schemes that combine fundamental novelty with technological impact.
Abstract We demonstrate heterogeneous integration of 5 µm-thick Y-cut lithium niobate (LN) films onto 2 µm-thick yttrium iron garnet (YIG) on gadolinium gallium garnet (GGG) via bonding and substrate removal, producing large, void-free active areas. The LN-on-YIG heterostructure enables low-loss acoustic waveguiding while maintaining sufficient strain-mediated coupling to spin waves in the buried YIG. Using this platform, we realize surface acoustic wave delay devices and observe acoustic-driven magnetic resonance at 655 MHz, with 6.66 dB/mm absorption and a − 44°/mm phase shift. Spatially resolved laser Doppler vibrometry further shows a magnetic field-dependent long-wavelength modulation of the propagating acoustic wave, possible evidence of driven energy exchange between the acoustic and magnetic spin system. These results establish heterogeneous integration as a wafer-scalable route to low-loss magnetoacoustic devices that combine high-performance piezoelectrics with ultralow-damping magnetic insulators, eliminating the need for lattice matching.
α-MnTe is among the earliest discovered altermagnets with experimental evidence of A-type antiferromagnetic order above room temperature and spin-split bands. Here, we conduct a theoretical investigation of its magnetism based on the general symmetry-adaptive tensorial spin model, which not only confirms a Néel temperature of 340 K induced by the dominant 1st and 3rd nearest-neighbor Heisenberg exchanges, but also the hexagonal planar Néel vector polarization of the ground state due to both the single-ion and the two-ion anisotropies. The 6-fold rotation symmetry along z prohibits an in-plane easy axis when only considering rank-2 and rank-4 interactions, revealing the continuous ground state degeneracy. Subsequently, we show that the triple-resistance states can be realized by adopting MnTe as the barrier in the sandwiched magnetic tunnel junctions. By deliberately matching the Brillouin zone-resolved spin transport of both the barrier and the electrode, tunneling magnetoresistance up to ~5300% is obtained. Our work not only provides a fine database of the magnetism and transmission for MnTe, but also sheds light on the application in high-density spintronic memory devices.
Magnetic droplets are highly nonlinear spin-wave solitons that can be excited in nanoscale spintronic devices with strong perpendicular magnetic anisotropy. Although extensively studied in nanocontact-based spin-torque oscillators, their stabilization in pure spin current-driven devices such as spin Hall nanooscillators (SHNOs) has remained elusive. Here, we micromagnetically demonstrate the robust stabilization of non-propagating high-frequency droplets in CMOS-compatible W/CoFeB/MgO nanoconstriction SHNOs under oblique magnetic fields. While the constriction geometry gives rise to noncircular droplet shapes in an inhomogeneous effective field landscape, stable droplet modes exhibiting complete core magnetization reversal and pronounced hysteresis are observed. At lower drive currents, droplets display breathing oscillations with periodic expansion and contraction, whereas higher drive currents lead to drift, deformation, and the emergence of sidebands around the fundamental frequency. Tuning the strength and orientation of the applied magnetic field alters the effective field landscape, allowing droplets to escape confinement and propagate over distances exceeding 2 μm.
