Energy-efficient control of magnetization without the help of a magnetic field is a key goal of spintronics. Purely heat-induced single-pulse all-optical toggle switching has been demonstrated, but so far only in Gd-based amorphous ferrimagnet films. In this work, we demonstrate toggle switching in films of the half-metallic ferrimagnetic Heusler alloys Mn2RuxGa, which have two crystallographically-inequivalent Mn sublattices. Moreover, we observe the switching at room temperature in samples that are immune to external magnetic fields in excess of 1 T, provided they exhibit a compensation point above room temperature. Observation of the effect in compensated ferrimagnets without Gd challenges our understanding of all-optical switching. The dynamic behavior indicates that Mn2RuxGa switches in 2 ps or less. Our findings widen the basis for fast optical switching of magnetization and break new ground for engineered materials that can be used for nonvolatile ultrafast switches using ultrashort pulses of light.

By combining Brillouin Light Scattering and micromagnetic simulations we studied the spin-wave dynamics of a Co/Pd thin film multilayer, features a stripe domain structure at remanence. The periodic up and down domains are separated by cork-screw type domain walls. The existence of these domains causes a scattering of the otherwise bulk and surface spin-wave modes, which form mode families, similar to a one dimensional magnonic crystal. The dispersion relation and mode profiles of spin waves are measured for transferred wave vector parallel and perpendicular to the domain axis.The possibility to use spin-waves (SW) to excite, transmit, store, and retrieve electric signals as well as to perform logical operations has fueled a new spectrum of research in the wavebased signal processing technology [1-4]. Usually, magnonic crystals (MC), i.e. arrays of macroscopic magnetic stripes [5], dots [6], antidots [7], etched grooves or pits[1], periodic variations of the internal magnetic field [9] and saturation magnetization by ion implantation [10], are employed to control the flow of SWs. Magnetostatic surface SWs or the Damon-Eshbach (DE) SW modes, which propagate perpendicular to the in-plane (IP) magnetization direction, are promising in this context because of their large group velocities (vg) and low attenuation.Consequently, significant progress has been made towards the practical realization of magnonic devices in terms of the on-chip generation, directional channeling, detection and manipulation of SWs. However, to realize the experimental geometry, a large magnetic field has to be applied to enforce the magnetization perpendicular to the SW propagation direction. This is a major obstacle to the implementation of a MC into a practical device. A way out is to use the Oersted field generated from an underlying current-carrying stripe [11][12], which is still plagued by the problem of generation of waste heat which increases with increasing data processing speed. Moreover, the fabrication of periodic nanostructures involves high-precision electron-beam lithography which is very complex and expensive. An alternative approach to overcome these fundamental drawbacks is to take recourse to the spin dynamics in the remanent state, which is more suitable for nanoscale device applications, as it does not require any stand-by power once initialized.In the literature, only few reports exist on the magnetization dynamics for systems with an inhomogeneous magnetization distribution containing domains and domain walls. Most commonly studied is a periodic or non-periodic distribution of magnetic units of up and down domains (parallel, labyrinthine, bubble-like domains) [13][14][15][16][17][18][19], separated by negligibly thin, onedimensional domain walls. Such domains appear in magnetic thin films with a perpendicular anisotropy smaller than the demagnetizing energy if the film thickness is higher than a critical value tc, which is, in turn, dependent on the perpendicular anisotropy constant, saturation magnetization and the exc...

Interfacial Dzyaloshinskii-Moriya interaction (IDMI) is important for its roles in stabilizing the skyrmionic lattice as well as soliton-like domain wall motion leading towards new generation spintronic devices. However, achievement and detection of IDMI is often hindered by various spurious effects. Here, we demonstrate the occurrence of IDMI originating primarily from W/CoFeB interface in technologically important W/CoFeB/SiO2 heterostructures using Brillouin light scattering technique. Due to the presence of IDMI, we observe asymmetry in the peak frequency and linewidth of the spin-wave spectra in the Damon-Eshbach (DE) geometry at finite k wave-vectors. The DMI constant is found to scale as the inverse of CoFeB thickness, over the whole studied thickness range, confirming the presence of IDMI in our system without any extrinsic effects. Importantly, the W/CoFeB interface shows no degradation down to sub-nanometer CoFeB thickness, which would be useful for devices that aim to use pronounced interface effects.

Understanding how a single laser pulse can toggle magnetization in a compensated 3d ferrimagnet is a critical problem in ultrafast magnetism. To resolve it, we test single-shot all-optical switching of magnetization in Mn 2 Ru x Ga at different temperatures using femto-to picosecond pulses in the visible to far-infrared spectral ranges. The switching process is found to be independent of photon energy, but strongly dependent on both the pulse duration and sample temperature. Switching is disabled whenever the starting temperature T 0 is above the compensation point of Mn 2 Ru x Ga, but as T 0 is lowered below compensation, increasingly longer pulses become capable of toggling the magnetization. We explain the observations in terms of a switching process driven by exchange relaxation of the angular momenta of the manganese sublattices, and propose a common framework to account for the similarities and differences of all-optical switching in Mn 2 Ru x Ga and GdFeCo alloys.