Effective Magnetic Anisotropy Research Articles

Engineering Co/MgO interface with heavy metals for voltage-controlled magnetic anisotropy effect

We have investigated the voltage-controlled magnetic anisotropy (VCMA) effect in Co/MgO junctions by inserting a sub-atomic layer of heavy metals at the interface. We evaluated an electrical control of the magnetic anisotropy by using a micro-magneto-optical Kerr effect magnetometer. The VCMA coefficient of the Co/MgO junctions increases with the insertion of an Ir or Pt layer and decreases with the insertion of an Os layer. These results imply that the VCMA coefficient can be engineered by doping heavy metals at the interface. The interface engineering using a heavy metal layer provides us with a method to control the VCMA coefficient over a wide range.

Voltage-gated spin-orbit torque switching in IrMn-based perpendicular magnetic tunnel junctions

In this work, IrMn-based perpendicular magnetic tunnel junctions (MTJs) are investigated. By inserting a thin W layer at an antiferromagnet/ferromagnet (AFM/FM) interface, we enhance the annealing temperature to 355 °C and obtain a high tunnel magnetoresistance ratio of 127%. Subsequently, field-free spin–orbit torque (SOT) switching of perpendicular MTJ is realized thanks to the in-plane exchange bias generated at the AFM/FM interface. Moreover, by applying a gate voltage, a coercive field is effectively decreased due to the voltage-controlled magnetic anisotropy (VCMA) effect. Finally, through the interplay of the SOT and VCMA effects, the critical switching current density is dramatically reduced by 73% (to 2.4 MA/cm2) and the total writing power consumption is decreased by 84% when a gate voltage of 0.76 V is applied. These findings pave the way for the practical applications of the IrMn-based perpendicular MTJs in low-power magnetic random-access memory.

Micromagnetic and morphological characterization of heteropolymer human ferritin cores.

The physical properties of in vitro iron-reconstituted and genetically engineered human heteropolymer ferritins were investigated. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), electron energy-loss spectroscopy (EELS), and 57Fe Mössbauer spectroscopy were employed to ascertain (1) the microstructural, electronic, and micromagnetic properties of the nanosized iron cores, and (2) the effect of the H and L ferritin subunit ratios on these properties. Mössbauer spectroscopic signatures indicate that all iron within the core is in the high spin ferric state. Variable temperature Mössbauer spectroscopy for H-rich (H21/L3) and L-rich (H2/L22) ferritins reconstituted at 1000 57Fe/protein indicates superparamagnetic behavior with blocking temperatures of 19 K and 28 K, while HAADF-STEM measurements give average core diameters of (3.7 ± 0.6) nm and (5.9 ± 1.0) nm, respectively. Most significantly, H-rich proteins reveal elongated, dumbbell, and crescent-shaped cores, while L-rich proteins present spherical cores, pointing to a correlation between core shape and protein shell composition. Assuming an attempt time for spin reversal of τ 0 = 10-11 s, the Néel-Brown formula for spin-relaxation time predicts effective magnetic anisotropy energy densities of 6.83 × 104 J m-3 and 2.75 × 104 J m-3 for H-rich and L-rich proteins, respectively, due to differences in surface and shape contributions to magnetic anisotropy in the two heteropolymers. The observed differences in shape, size, and effective magnetic anisotropies of the derived biomineral cores are discussed in terms of the iron nucleation sites within the interior surface of the heteropolymer shells for H-rich and L-rich proteins. Overall, our results imply that site-directed nucleation and core growth within the protein cavity play a determinant role in the resulting core morphology. Our findings have relevance to iron biomineralization processes in nature and the growth of designer's magnetic nanoparticles within recombinant apoferritin nano-templates for nanotechnology.

Giant unilateral electric-field control of magnetic anisotropy in MgO/Rh2CoSb heterojunctions.

A large voltage-controlled magnetic anisotropy (VCMA) effect is highly desirable for applications of voltage-torque magnetic random access memory. In this work, the dependence of magnetic anisotropy (MA) on the electric field in a MgO-based heterojunction consisting of a new Heusler alloy, Rh2CoSb, is studied using first-principles calculations. We find that the Rh-terminated MgO/Rh2CoSb heterojunction has a perpendicular MA and a giant VCMA coefficient of 7024 fJ V-1 m-1. Furthermore, the VCMA coefficient shows a characteristic of dependence on the electric-field direction. The origins of these behaviors are elucidated by orbital-resolved MA and second-order perturbation theoretical analysis. As the spin-down states of the in-plane orbital, dxy, are close to the Fermi level, the shift of these states induced by the electric field gives rise to significant changes of magnetic anisotropy energy, which is mainly responsible for the giant VCMA effect.

Validity of DFT-based spin-orbit torque calculation for perpendicular magnetic anisotropy in iron thin films

In this study, the validity of our DFT-based self-developed JunPy+SOT calculation method has been rigorously confirmed by the perpendicular magnetic anisotropy (PMA) induced effective magnetic anisotropy field of 5.6 kOe in a 1.5 nm-thick iron thin film. The angular dependence of the magnetic anisotropy energy (MAE) and the total spin-orbit torque (SOT) indicate the uniaxial PMA corresponding to the out-of-plane rotations of the magnetization. Our results agree with the conventional MAE calculation but provide deeper insights into atomistic spin dynamics of local magnetic moments. The main advantage of this method is that the well-decomposed layer-resolved SOT and SOC-dominated spin current accumulation, which exhibit maximum magnitude but opposite sign at the surface, provide comprehensive physical understanding in angular momentum transfer between spin and orbital, competition between SOT and spin current accumulation, and precise spin torque acting on each local magnetic moment that is crucial for the atomistic spin dynamics especially in magnetic heterostructures.

Controlling magnetic anisotropy in nickel films on LiNbO3

Nickel thin films, deposited on 128° Y-cut LiNbO3, and subsequently annealed at low temperature (≈ 300 °C), exhibit a number of interesting and unusual magnetic properties. These include: hysteresis branch crossings, negative Barkhausen jumps, square hysteresis loops (squareness > 0.99), Stoner-Wohlfarth behavior, and a well-defined, uniaxial, magnetic anisotropy. Previous work suggests the magnetic anisotropy is created by magneto-elastic coupling between the film and the underlying substrate. The difference of thermal coefficient of expansion between film and substrate was thought to generate a well-defined strain upon cooling from the annealing temperature. Here we show that the changes in the effective magnetic anisotropy field are directly correlated with thermal strain. This mechanism provides a technique for creating and modifying magnetic anisotropy in a controlled fashion.

Role of Dipolar Interactions on the Determination of the Effective Magnetic Anisotropy in Iron Oxide Nanoparticles

Challenging magnetic hyperthermia (MH) applications of immobilized magnetic nanoparticles require detailed knowledge of the effective anisotropy constant (Keff ) to maximize heat release. Designing optimal MH experiments entails the precise determination of magnetic properties, which are, however, affected by the unavoidable concurrence of magnetic interactions in common experimental conditions. In this work, a mean-field energy barrier model (ΔE), accounting for anisotropy (EA ) and magnetic dipolar (ED ) energy, is proposed and used in combination with AC measurements to a specifically developed model system of spherical magnetic nanoparticles with well-controlled silica shells, acting as a spacer between the magnetic cores. This approach makes it possible to experimentally demonstrate the mean field dipolar interaction energy prediction with the interparticle distance, dij , ED ≈1/dij 3 and obtain the EA as the asymptotic limit for very large dij . In doing so, Keff uncoupled from interaction contributions is obtained for the model system (iron oxide cores with average sizes of 8.1, 10.2, and 15.3nm) revealing to be 48, 23, and 11kJm-3 , respectively, close to bulk magnetite/maghemite values and independent from the specific spacing shell thicknesses selected for the study.

Hyperthermia of Magnetically Soft-Soft Core-Shell Ferrite Nanoparticles

Magnetically soft-soft MnFe2O4-Fe3O4 core-shell nanoparticles were synthesized through a seed-mediated method using the organometallic decomposition of metal acetyl acetonates. Two sets of core-shell nanoparticles (S1 and S2) of similar core sizes of 5.0 nm and different shell thicknesses (4.1 nm for S1 and 5.7 nm for S2) were obtained by changing the number of nucleating sites. Magnetic measurements were conducted on the nanoparticles at low and room temperatures to study the shell thickness and temperature dependence of the magnetic properties. Interestingly, both core-shell nanoparticles showed similar saturation magnetization, revealing the ineffective role of the shell thickness. In addition, the coercivity in both samples displayed similar temperature dependencies and magnitudes. Signatures of spin glass (SG) like behavior were observed from the field-cooled temperature-dependent magnetization measurements. It was suggested to be due to interface spin freezing. We observed a slight and non-monotonic temperature-dependent exchange bias in both samples with slightly higher values for S2. The effective magnetic anisotropy constant was calculated to be slightly larger in S2 than that in S1. The magnetothermal efficiency of the chitosan-coated nanoparticles was determined by measuring the specific absorption rate (SAR) under an alternating magnetic field (AMF) at 200-350 G field strengths and frequencies (495.25-167.30 kHz). The S2 nanoparticles displayed larger SAR values than the S1 nanoparticles at all field parameters. A maximum SAR value of 356.5 W/g was obtained for S2 at 495.25 kHz and 350 G for the 1 mg/mL nanoparticle concentration of ferrogel. We attributed this behavior to the larger interface SG regions in S2, which mediated the interaction between the core and shell and thus provided indirect exchange coupling between the core and shell phases. The SAR values of the core-shell nanoparticles roughly agreed with the predictions of the linear response theory. The concentration of the nanoparticles was found to affect heat conversion to a great extent. The in vitro treatment of the MDA-MB-231 human breast cancer cell line and HT-29 human colorectal cancer cell was conducted at selected frequencies and field strengths to evaluate the efficiency of the nanoparticles in killing cancer cells. The cellular cytotoxicity was estimated using flow cytometry and an MTT assay at 0 and 24 h after treatment with the AMF. The cells subjected to a 45 min treatment of the AMF (384.50 kHz and 350 G) showed a remarkable decrease in cell viability. The enhanced SAR values of the core-shell nanoparticles compared to the seeds with the most enhancement in S2 is an indication of the potential for tailoring nanoparticle structures and hence their magnetic properties for effective heat generation.

Testing the validity of the core-shell-surface layer model on the size dependence of effective magnetic anisotropy in magnetic nanoparticles

The stability of the stored information in magnetic recording media depends on the anisotropy energy Ea (=KeffV) of nanoparticles (NPs) of volume V or diameter D. Therefore, it is important to know how the effective anisotropy constant Keff varies with size D of the NPs. In a recent paper [Appl. Phys. Lett. 110, 222409 (2017)], the observed Keff versus D variation in NPs of maghemite (γ-Fe2O3) was explained on the basis of the core-shell-surface layer (CSSL) model given by Eq.: Keff = Kb + (6KS/D) +Ksh{[1-(2d/D)]−3–1}, where Kb,KS, and Ksh are the anisotropy constants of spins in the core, surface layer, and a shell of thickness d, respectively. This CSSL model is an extension of an earlier core-surface layer (CSL) model described by Keff = Kb + (6KS/D) [Phys. Rev. Lett. 72, 282 (1994)] proposed to explain the Keff versus D variation in Fe NPs. For the NPs of γ-Fe2O3, the additional term of the CSSL model involving Ksh was found to be necessary to fit the data for sizes D < 5 nm. In this paper, we report the validity of the CSSL model for NPs of several other systems viz. Co, Ni, NiO, and Fe3O4 using the available data from literature. In selecting the data, care was taken to consider data only for non-interacting NPs since the interparticle interactions generally overshadow the actual value of Keff in NPs. It is shown that the new CSSL model describes very well the Keff vs. D variation for all particle sizes whereas the CSL model fails for smaller particles with the notable exception of Fe NPs. This validation of the CSSL model for the NPs of Co, Ni, NiO, Fe3O4, and γ-Fe2O3 suggests its general validity for magnetic NPs. Discussion is also presented on the comparative magnitudes of the parameters Kb, KS, and Ksh obtained from the fits to the CSSL model.

Temperature dependence of magnetic anisotropy in a cylindrical Fe65Pd35 nanowire array

Fe65Pd35 cylindrical nanowires (NWs) were synthesized in commercial anodic alumina porous templates via potentiostatic electrodeposition. The morphology, composition, and crystalline structure were analyzed by scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. The NWs obtained are (10 ± 2) μm long and (200 ± 20) nm in diameter, with a polycrystalline microstructure. Magnetic properties were investigated by measuring the Zero Field Cooling-Field Cooling magnetization curves and hysteresis loops in the temperature range 10 K to 350 K. The magnetization easy axis is determined to be along the NWs axis, indicating strong anisotropy in this direction, which cannot be accounted for by only considering shape anisotropy. The hysteresis loops were fitted using the law of approach to saturation, obtaining the effective anisotropy field HA and the effective anisotropy constant Keff value for different temperatures. The blocking temperature TB dependence on the magnetic field H was also analyzed, indicating that a blocked magnetic contribution is present, arising from the smaller grains in the NWs. The observed enhancement in the effective magnetic anisotropy of the array throughout the studied temperature range is explained by considering magnetic interactions among these nanograins.

Two monofluoride-bridged DyIII dimers with different magnetization dynamics

As a monoatomic bridge, fluoride ion can transmit efficient magnetic interaction between lanthanide ions but its effect on tuning the magnetization dynamics has not been well understood. Herein, two monofluoride-bridged dinuclear dysprosium complexes [Dy2F(bbpen)2(EtOH)2]Br·EtOH (1) and [Dy2F(bbppy)2]Br·2EtOH (2) with Dy-F-Dy angles of ∼178° and their diamagnetic-ion diluted analogues 1´ and 2´ were synthesized. Magnetic studies reveal that 1 and 1´ barely show any magnetization dynamics, but 2 and 2´ exhibit strong magnetization dynamics. Systematical experimental analysis combined with ab initio calculations reveals that the different magnetization dynamics between 1 and 2 mainly originate from the effect of magnetic anisotropy by terminal ligand and bridging group of the chelating ligand, and the fluoride bridge can effectively suppress the quantum tunneling of the magnetization and turn on Orbach process in 2.

Anomalous Hall Effect in Epitaxial Thin Films of the Hexagonal Heusler MnPtGa Noncollinear Hard Magnet

AbstractMaterials hosting noncollinear magnetic ordering and sizeable spin‐orbit coupling can manifest perpendicular magnetic anisotropy and a Berry curvature‐driven intrinsic anomalous Hall effect. In this work, the structural, magnetic, and magnetotransport properties of crystalline hexagonal Heusler MnPtGa epitaxial thin films are reported. The centrosymmetric MnPtGa films (P63/mmc space group) crystallize with a preferred c‐axis (0001) crystal orientation. Along this crystallographic direction, the MnPtGa films exhibit preferential perpendicular magnetic anisotropy, below the Curie temperature TC = 263 K, with a large effective uniaxial magnetic anisotropy Keff = 0.735 MJ m−3, at 150 K. In addition, the MnPtGa system undergoes a thermally induced spin reorientation transition below Tsr = 160 K, which marks the onset of a noncollinear spin‐canted state. The anomalous Hall conductivity (AHC) of MnPtGa films exhibits a nonmonotonic behavior as a function of temperature, which changes sign at T* = 110 K. Concurrently with the reported unusual dependence of the AHC on the longitudinal conductivity in MnPtGa crystalline thin films, these findings strongly suggest an anomalous Hall effect of intrinsic origin, driven by a momentum‐space Berry curvature mechanism, as supported by first‐principle calculations.

Design of VGSOT-MTJ-Based Logic Locking for High-Speed Digital Circuits

Emerging spintronics devices in recent research have received much interest in various fields. Their unique physical aspects are being explored to keep Moore’s law alive. Therefore, the hardware security aspects of system-on-a-chip (SoC) designs using spintronics devices becomes important. Magnetic tunnel junctions (MTJ) are a potential candidate in spintronics-based devices for beyond-CMOS applications. This work uses voltage-gated spin-orbit torque-assisted magnetic tunnel junction (VGSOT-MTJ) based on the Verilog-A behavioral model to design a possible logic-locking system for hardware security. Compared with the SOT MTJ, which uses a heavy metal strip below the MTJ stack, VGSOT-MTJ has an antiferromagnetic (AFM) strip that utilizes the voltage-controlled magnetic anisotropy (VCMA) effect to significantly reduce the JSOT,critical. To design the logic-locking block, we performed a Monte Carlo analysis to account for the effect of process variation (PV) on critical MTJ parameters. Eye diagram tests and mask designing were performed, which included the effect of thermal noise and PV for high-speed digital circuit operations. Finally, transient performance was analyzed to demonstrate the VGSOT-MTJ’s ability to design logic-locking blocks from the circuit operation perspective.

Voltage-controlled magnetic anisotropy effect through a LiF/MgO hybrid tunneling barrier

Improving the perpendicular magnetic anisotropy (PMA) and voltage-controlled magnetic anisotropy (VCMA) properties are fundamentally important for the development of voltage-controlled magnetoresistive random access memories (VC-MRAM). Recently, we reported on a large increase in PMA at an Fe/MgO interface brought about by inserting an ultrathin LiF layer at the interface. In this paper, we investigate the PMA, VCMA, and TMR properties in MTJs with an Ir-doped ultrathin ferromagnetic layer and a LiF/MgO hybrid tunneling barrier. We observed a clear increase in the interfacial PMA by a factor of 2.5 when an ultrathin 0.25 nm LiF layer was inserted. A large VCMA coefficient, exceeding −300 fJ/Vm, was also achieved while maintaining the high TMR ratio and high interfacial PMA. These results demonstrate the high potential of interface engineering using ultrathin LiF layers for spintronic devices.

Understanding the Magnetic Microstructure through Experiments and Machine Learning Algorithms.

Advanced machine learning techniques have unfurled their applications in various interdisciplinary areas of research and development. This paper highlights the use of image regression algorithms based on advanced neural networks to understand the magnetic properties directly from the magnetic microstructure. In this study, Co/Pd multilayers have been chosen as a reference material system that displays maze-like magnetic domains in pristine conditions. Irradiation of Ar+ ions with two different energies (50 and 100 keV) at various fluences was used as an external perturbation to investigate the modification of magnetic and structural properties from a state of perpendicular magnetic anisotropy to the vicinity of the spin reorientation transition. Magnetic force microscopy revealed domain fragmentation with a smaller periodicity and weaker magnetic contrast up to the fluence of 1014 ions/cm2. Further increases in the ion fluence result in the formation of feather-like domains with a variation in local magnetization distribution. The experimental results were complemented with micromagnetic simulations, where the variations of effective magnetic anisotropy and exchange constant result in qualitatively similar changes in magnetic domains, as observed experimentally. Importantly, a set of 960 simulated domain images was generated to train, validate, and test the convolutional neural network (CNN) that predicts the magnetic properties directly from the domain images with a high level of accuracy (maximum 93.9%). Our work has immense importance in promoting the applications of image regression methods through the CNN in understanding integral magnetic properties obtained from the microscopic features subject to change under external perturbations.

Enhancing voltage-controlled magnetic anisotropy in Fe80B20/MgO/HfO2 thin films by dielectric constant modulation

The voltage-controlled magnetic anisotropy (VCMA) effect is the basis for ultralow-power spin manipulation in spintronic devices such as voltage-controlled magnetoresistive random-access memory (VC-MRAM). A larger VCMA coefficient $\ensuremath{\xi}$ is required to develop VC-MRAM with a higher density. Although $\ensuremath{\xi}$ is theoretically proportional to the dielectric constant ${\ensuremath{\varepsilon}}_{\mathrm{r}}$ of the tunnel barrier material, this relationship has not been experimentally examined. We systematically investigated the relationship between $\ensuremath{\xi}$ and ${\ensuremath{\varepsilon}}_{\mathrm{r}}$ in a ${\mathrm{Fe}}_{80}{\mathrm{B}}_{20}/\mathrm{MgO}/{\mathrm{HfO}}_{2}$ structure prepared by sputtering-based deposition. We successfully controlled ${\ensuremath{\varepsilon}}_{\mathrm{r}}$ while maintaining perpendicular magnetic anisotropy at the ${\mathrm{Fe}}_{80}{\mathrm{B}}_{20}/\mathrm{MgO}$ interface. Both ${\ensuremath{\varepsilon}}_{\mathrm{r}}$ and $\ensuremath{\xi}$ were observed to monotonically increase with ${\mathrm{HfO}}_{2}$, showing a positive correlation between $\ensuremath{\xi}$ and ${\ensuremath{\varepsilon}}_{\mathrm{r}}$. The maximum $\ensuremath{\xi}$ reached \ensuremath{-}92 \ifmmode\pm\else\textpm\fi{} 4 fJ/Vm with ${\ensuremath{\varepsilon}}_{\mathrm{r}}=19.6\ifmmode\pm\else\textpm\fi{}0.3$. This result experimentally demonstrated that the VCMA effect could be enhanced by increasing ${\ensuremath{\varepsilon}}_{\mathrm{r}}$.

Non-periodic input-driven magnetization dynamics in voltage-controlled parametric oscillator

Input-driven dynamical systems have attracted attention because their dynamics can be used as resources for brain-inspired computing. The recent achievement of human-voice recognition by spintronic oscillator also utilizes an input-driven magnetization dynamics. Here, we investigate an excitation of input-driven chaos in magnetization dynamics by voltage controlled magnetic anisotropy effect. The study focuses on the parametric magnetization oscillation induced by a microwave voltage and investigates the effect of random-pulse input on the oscillation behavior. Solving the Landau–Lifshitz–Gilbert equation, temporal dynamics of the magnetization and its statistical character are evaluated. In a weak perturbation limit, the temporal dynamics of the magnetization are mainly determined by the input signal, which is classified as input-driven synchronization. In a large perturbation limit, on the other hand, chaotic dynamics are observed, where the dynamical response is sensitive to the initial state. The existence of chaos is also identified by the evaluation of the Lyapunov exponent.

Standing spin wave excitation in Bi : YIG films via temperature-induced anisotropy changes and magneto-elastic coupling

Based on micromagnetic simulations and experimental observations of the magnetization and lattice dynamics after the direct optical excitation of the magnetic insulator Bi : YIG or indirect excitation via an optically opaque Pt/Cu double layer, we disentangle the dynamical effects of magnetic anisotropy and magneto-elastic coupling. The strain and temperature of the lattice are quantified via modeling ultrafast x-ray diffraction data. Measurements of the time-resolved magneto-optical Kerr effect agree well with the magnetization dynamics simulated according to the excitation via two mechanisms: the magneto-elastic coupling to the experimentally verified strain dynamics and the ultrafast temperature-induced transient change in the magnetic anisotropy. The numerical modeling proves that, for direct excitation, both mechanisms drive the fundamental mode with opposite phase. The relative ratio of standing spin wave amplitudes of higher-order modes indicates that both mechanisms are substantially active.

Structural and magnetic properties of Ni substituted FeCo alloy obtained through polyol process

Fe alloy powders with optimum magnetic properties are in demand for the fabrication of soft magnetic composites that find applications in power electronics and more electric vehicles. Fe-Co-Ni alloys with particles exhibiting spherical morphology and body-centered cubic structure are synthesized using a facile instant reduction polyol process. Curie temperatures from 840 to 760 °C are obtained with Ni substitution in the range of 7–14 at.%. The effective magnetic anisotropy realized using a modified law of approach to saturation and the Curie temperature studies suggests an additional amorphous phase that affects the magnetic behavior. The multidomain Fe-Co-Ni alloy particles have the potential for high-temperature applications as their effective magnetic anisotropies of 20–25 kJ/m3 are lower than Fe and FeCo powders.

Tuning the Dynamics of Chiral Domain Walls of Ferrimagnetic Films by Magnetoionic Effects

The manipulation of magnetism with a gate voltage is expected to lead the way towards the realization of energy-efficient spintronics devices and high-performance magnetic memories. Exploiting magneto-ionic effects under micro-patterned electrodes in solid-state devices adds the possibility to modify magnetic properties locally, in a non-volatile and reversible way. Tuning magnetic anisotropy, magnetization and Dzyaloshinskii-Moriya interaction allows modifying at will the dynamics of non trivial magnetic textures such as skyrmions and chiral domain walls in magnetic race tracks. In this work, we illustrate efficient magneto-ionic effects in a ferrimagnetic Pt/Co/Tb stack using a ZrO2 thin layer as a solid state ionic conductor. When a thin layer of terbium is deposited on top of cobalt, it acquires a magnetic moment that aligns antiparallel to that of cobalt, reducing the effective magnetization. Below the micro-patterned electrodes, the voltage-driven migration of oxygen ions in a ZrO2 towards the ferrimagnetic stack partially oxidizes the Tb layer, leading to the local variation not only of the spontaneous magnetization, but also of the effective magnetic anisotropy and of the Dzyaloshinskii-Moriya interaction. This leads to a huge increase of the domain wall velocity, which varies from 10 m/s in the pristine state to 250 m/s after gating. This non-volatile and reversible tuning of the domain wall dynamics may lead to applications to reprogrammable magnetic memories or other spintronic devices.