The manipulation of skyrmions by surface acoustic waves (SAW) has garnered significant interest in the field of spintronic devices. Previous studies established that skyrmions can be generated and moved by strain pulses. In this study, we propose that sawtooth-SAWs can be used to drive a ratchet motion of magnetic skyrmions in the presence of pinning centers. This results in a net motion of the skyrmions orthogonal to the continuously applied SAW. The ratchet motion is fundamentally caused by non-vanishing pinning, so that a certain strain gradient magnitude is required to overcome pinning and start skyrmion motion. We demonstrate the feasibility of our concept by micromagnetic simulations and analytical model calculations.

The manipulation of skyrmions by surface acoustic waves (SAW) has garnered significant interest in the field of spintronic devices. Previous studies established that skyrmions can be generated and moved by strain pulses. In this study, we propose that sawtooth-SAWs can be used to drive a ratchet motion of magnetic skyrmions in the presence of pinning centers. This results in a net motion of the skyrmions orthogonal to the continuously applied SAW. The ratchet motion is fundamentally caused by non-vanishing pinning, so that a certain strain gradient magnitude is required to overcome pinning and start skyrmion motion. We demonstrate the feasibility of our concept by micromagnetic simulations and analytical model calculations.

We investigate spin dynamics in α-Fe2O3/Ni80Fe20 (Py) heterostructures, uncovering a robust mechanism for in-situ modulation of ferromagnetic resonance (FMR) through precise control of temperature, applied magnetic field and crystal orientation. Employing cryogenic ferromagnetic resonance spectroscopy, we demonstrate that the interfacial coupling between the Néel vector of α-Fe2O3 and the magnetization of the Py layer is highly tunable across the Morin transition temperature (TM). Our experiments reveal distinct resonance behavior for different crystal orientations, highlighting the pivotal role of exchange coupling strength in dictating FMR frequencies. Theoretical modeling corroborates the experimental findings, elucidating the dependence of coupling on the relative alignment of the Néel vector and ferromagnetic magnetization. Notably, we achieve significant modulation of FMR frequencies by manipulating the Néel vector configuration, facilitated by temperature variations, applied magnetic fields and crystal orientation adjustments. These advancements demonstrate the potential for dynamic control of spin interactions in AFM/FM heterostructures, paving the way for the development of advanced spintronic devices with tunable magnetic properties. Our work provides critical insights into the fundamental interactions governing hybrid spin systems and opens new avenues for the design of versatile, temperature-responsive magnetoelectronic applications.

We investigate spin dynamics in α-Fe2O3/Ni80Fe20 (Py) heterostructures, uncovering a robust mechanism for in-situ modulation of ferromagnetic resonance (FMR) through precise control of temperature, applied magnetic field and crystal orientation. Employing cryogenic ferromagnetic resonance spectroscopy, we demonstrate that the interfacial coupling between the Néel vector of α-Fe2O3 and the magnetization of the Py layer is highly tunable across the Morin transition temperature (TM). Our experiments reveal distinct resonance behavior for different crystal orientations, highlighting the pivotal role of exchange coupling strength in dictating FMR frequencies. Theoretical modeling corroborates the experimental findings, elucidating the dependence of coupling on the relative alignment of the Néel vector and ferromagnetic magnetization. Notably, we achieve significant modulation of FMR frequencies by manipulating the Néel vector configuration, facilitated by temperature variations, applied magnetic fields and crystal orientation adjustments. These advancements demonstrate the potential for dynamic control of spin interactions in AFM/FM heterostructures, paving the way for the development of advanced spintronic devices with tunable magnetic properties. Our work provides critical insights into the fundamental interactions governing hybrid spin systems and opens new avenues for the design of versatile, temperature-responsive magnetoelectronic applications.

Source data from ferromagnetic resonance experiments and micromagnetic simulations in tetmag software (https://github.com/R-Hertel/tetmag), used in the paper "Collective Spin-Wave Dynamics in Gyroid Ferromagnetic Nanostructures" in ACS Applied Materials & Interfaces (https://doi.org/10.1021/acsami.4c02366).

Source data from ferromagnetic resonance experiments and micromagnetic simulations in tetmag software (https://github.com/R-Hertel/tetmag), used in the paper "Collective Spin-Wave Dynamics in Gyroid Ferromagnetic Nanostructures" in ACS Applied Materials & Interfaces (https://doi.org/10.1021/acsami.4c02366).