scholarly journals Multiple Walker Breakdowns in Magnetic Multilayers

2021 ◽  
Author(s):  
Joon Moon ◽  
Jaesung Yoon ◽  
Kitae Kim ◽  
Seong-Hyub Lee ◽  
Dae-Yun Kim ◽  
...  
Keyword(s):  
Domain Wall ◽  
Domain Walls ◽  
Multilayer Films ◽  
Magnetic Multilayers ◽  
Magnetic Multilayer ◽  
Phase Boundaries ◽  
Domain Wall Dynamics ◽  
Domain Wall Velocity ◽  
Magnetic Layers ◽  
Magnetic Dipole Field

Abstract Herein, we report an exotic domain-wall dynamics showing double Walker breakdowns in magnetic multilayer films composed of two magnetic layers. Such multiple Walker breakdowns are attributed to the internal magnetic dipole field, which is antisymmetric on the domain walls of the lower and upper magnetic layers. A micromagnetic simulation shows four phases of the domain-wall dynamics, which result in a phase diagram with the phase boundaries of the double Walker breakdown fields. Such double Walker breakdowns lead to two minima in the variation of the domain-wall velocity, as often observed experimentally.

Domain Wall Dynamics in a Double-Layer Magnetic Film with Different Uniaxial Anisotropy the Layers

2009 ◽  
Vol 152-153 ◽  
pp. 365-368
Author(s):  
V.V. Randoshkin ◽  
N.N. Sysoev ◽  
A.A. Mastin
Keyword(s):  
Magnetic Field ◽  
Domain Wall ◽  
Uniaxial Anisotropy ◽  
Steady Motion ◽  
Magnetic Film ◽  
Unsteady Motion ◽  
Threshold Field ◽  
Wall Velocity ◽  
Domain Wall Dynamics ◽  
Domain Wall Velocity

Motion of an isolated domain wall in a double-layered magnetic film, whose layers differ in their uniaxial anisotropy only, is investigated through solving the Slonczewski equations by a numerical method. Dependences of the threshold field and the limiting velocity of disruption of the steady state motion of the film on the anisotropy and thicknesses of layers are obtained. Also, we showed that in domain wall unsteady motion regime, a dependence of domain wall velocity from magnetic field contains a series velocity peaks that relies on steady motion of Bloch lines across film and domain wall velocity in such cases can’t be simply increased by increasing magnetic field and restricted by some volume.

Transport Properties in All Oxide Magnetic Multilayers

2008 ◽  
Vol 587-588 ◽  
pp. 318-322
Author(s):  
H. Sobreiro ◽  
B. Berini ◽  
N. Keller ◽  
David S. Schmool
Keyword(s):  
Transport Properties ◽  
Electrical Transport ◽  
Molecular Beam ◽  
Magnetic Layer ◽  
Magnetic Multilayers ◽  
Magnetic Multilayer ◽  
Electrical Transport Properties ◽  
Appreciable Increase ◽  
Magnetic Layers ◽  
Laser Mbe

The all oxide magnetic multilayer system [LaNiO3/SmFeO3]n (for n = 1 and 2), grown on single crystal SrTiO3(100) substrates, has been produced using the laser MBE (Molecular Beam Epitaxy) technique. We have made a systematic study of the electrical transport properties in the temperature range from 15–300K. As part of this work, we have made a detailed study of the metallic properties of the LaNiO3 layer as a function of the oxygen partial pressure (pO2) and substrate temperature (TS). We have measured magnetic layers of SmFeO3 with LaNiO3 electrodes as a function of the magnetic layer thickness (10 – 470 nm). A non-metallic behaviour is observed with evidence of a “hopping” mechanism at low temperatures. For the n = 2 multilayers, we have measured the temperature dependence of resistance for the sample series with varying LaNiO3 interlayer thickness (t = 2 – 30 nm). We observe an appreciable increase of the low temperature resistance for the interlayer thicknesses between 3.75 – 7.5 nm. This could indicate a change in coupling from ferromagnetic to antiferromagnetic between the magnetic layers.

scholarly journals Electric manipulation of domain walls in magnetic Weyl semimetals via the axial anomaly

2021 ◽  
Vol 10 (5) ◽  
Author(s):  
Julia Hannukainen ◽  
Alberto Cortijo ◽  
Jens H Bardarson ◽  
Yago Ferreiros
Keyword(s):  
Domain Wall ◽  
Electric Field ◽  
Domain Walls ◽  
Direct Proof ◽  
Chiral Anomaly ◽  
Axial Anomaly ◽  
Domain Wall Dynamics ◽  
Weyl Semimetal ◽  
Electric And Magnetic Fields ◽  
Weyl Semimetals

We show how the axial (chiral) anomaly induces a spin torque on the magnetization in magnetic Weyl semimetals. The anomaly produces an imbalance in left- and right-handed chirality carriers when non-orthogonal electric and magnetic fields are applied. Such imbalance generates a spin density which exerts a torque on the magnetization, the strength of which can be controlled by the intensity of the applied electric field. We show how this results in an electric control of the chirality of domain walls, as well as in an improvement of the domain wall dynamics, by delaying the onset of the Walker breakdown. The measurement of the electric field mediated changes in the domain wall chirality would constitute a direct proof of the axial anomaly. Additionally, we show how quantum fluctuations of electronic Fermi arc states bound to the domain wall naturally induce an effective magnetic anisotropy, allowing for high domain wall velocities even if the intrinsic anisotropy of the magnetic Weyl semimetal is small.

Nonlinear domain-wall dynamics in a system of two magnetic layers

1999 ◽  
Vol 89 (4) ◽  
pp. 734-739 ◽  
Author(s):  
A. K. Zvezdin ◽  
V. V. Kostyuchenko
Keyword(s):  
Domain Wall ◽  
Domain Wall Dynamics ◽  
Magnetic Layers

scholarly journals Ultrafast current and field driven domain-wall dynamics in van der Waals antiferromagnet MnPS3

2020 ◽  
Author(s):  
Ignacio Alliati ◽  
Richard Evans ◽  
Kostya Novoselov ◽  
Elton Santos
Keyword(s):  
Magnetic Fields ◽  
Domain Wall ◽  
Domain Walls ◽  
Van Der Waals ◽  
Honeycomb Structure ◽  
Magnetic Domains ◽  
Electric Currents ◽  
Functional Feature ◽  
Additional Degree ◽  
Domain Wall Dynamics

Abstract The discovery of magnetism in two-dimensional (2D) van der Waals (vdW) materials1–4 has flourished a new endeavour of fundamental problems in magnetism as well as potential applications in computing, sensing and storage technologies5–10. Of particular interest are antiferromagnets 11, 12, which due to their intrinsic antiferromagnetic exchange coupling show several advantages in relation to ferromagnets such as robustness against external magnetic perturbations. This property is one of the cornerstones of antiferromagnets13 and implies that in formation stored in antiferromagnetic domains is invisible to applied magnetic fields preventing it from being erased or manipulated. Here we show that, despite this fundamental understanding, the magnetic domains of recently discovered 2D vdW MnPS3 antiferromagnet14, 15 can be controlled via external magnetic fields and electric currents. We realize ultrafast domain-wall dynamics with velocities up to ∼1500 m s−1 and ∼3000 m s−1 respectively to a broad range of field magnitudes (0.0001−22 T) and current densities (108 − 1010 A cm−2). Both domain wall dynamics are determined by the edge terminations which generated uncompensated spins following the underlying symmetry of the honeycomb structure. We find that edge atoms belonging to different magnetic sublattices function as geometrical constrictions preventing the displacement of the wall, whereas having atoms of the same sublattice at both edges of the material allows for the field-driven domain wall motion which is only limited by the spin-flop transition of the antiferromagnet beyond 25 T. Conversely, electric currents can induce motion of domain walls in most of the edges except those where the two sublattices are present at the borders (e.g. armchair edges). Furthermore, the orientation of the layer relative to the current flow provides an additional degree of freedom for controlling and manipulating magnetic domains in MnPS3. Our results indicate that the implementation of 2D vdW antiferromagnets in real applications requires the engineering of the layer edges which enables an unprecedented functional feature in ultrathin device platforms.

scholarly journals Ferroelectric domain wall dynamics characterized with X-ray photon correlation spectroscopy

2018 ◽  
Vol 115 (29) ◽  
pp. E6680-E6689 ◽  
Author(s):  
Semën Gorfman ◽  
Alexei A. Bokov ◽  
Arman Davtyan ◽  
Mario Reiser ◽  
Yujuan Xie ◽  
...  
Keyword(s):  
Domain Wall ◽  
Domain Walls ◽  
Photon Correlation Spectroscopy ◽  
Domain Wall Motion ◽  
Correlation Spectroscopy ◽  
X Rays ◽  
Photon Correlation ◽  
X Ray ◽  
Domain Wall Dynamics ◽  
Speckle Patterns

Technologically important properties of ferroic materials are determined by their intricate response to external stimuli. This response is driven by distortions of the crystal structure and/or by domain wall motion. Experimental separation of these two mechanisms is a challenging problem which has not been solved so far. Here, we apply X-ray photon correlation spectroscopy (XPCS) to extract the contribution of domain wall dynamics to the overall response. Furthermore, we show how to distinguish the dynamics related to the passing of domain walls through the periodic (Peierls) potential of the crystal lattice and through the random potential caused by lattice defects (pinning centers). The approach involves the statistical analysis of correlations between X-ray speckle patterns produced by the interference of coherent synchrotron X-rays scattered from different nanosize volumes of the crystal and identification of Poisson-type contribution to the statistics. We find such a contribution in the thermally driven response of the monoclinic phase of a ferroelectric PbZr0.55Ti0.45O3 crystal and calculate the number of domain wall jumps in the studied microvolume.

Electrodeposited Magnetic Multilayers

1996 ◽  
Vol 451 ◽  
Author(s):  
W. Schwarzacher ◽  
M. Alper ◽  
R. Hart ◽  
G. Nabiyouni ◽  
I. Bakonyi ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Giant Magnetoresistance ◽  
Single Layer ◽  
Multilayer Films ◽  
Magnetic Multilayers ◽  
Magnetic Multilayer ◽  
Cu Film ◽  
Magnetic Metal ◽  
Cu Foil

ABSTRACTElectrodeposited magnetic multilayer films consisting of alternating layers of a ferromagnetic and a non-magnetic metal may exhibit giant magnetoresistance (GMR), but the effect is very sensitive to whether deposition is carried out under potentiostatic or galvanostatic control, and the choice of substrate. The texture of Co-Ni-Cu/Cu superlattices grown on polycrystalline (100)-textured Cu plates and (HO)-textured Cu foil under potentiostatic control depended on that of the substrate, while comparable superlattices grown under galvanostatic control had a predominantly (111) texture. The films grown under galvanostatic control generally exhibit AMR or smaller GMR. The magnetic and magnetotransport properties of Co-Ni-Cu/Cu superlattices and a single-layer Co-Ni-Cu film electrodeposited directly onto n-GaAs (100) are also described, and evidence is presented for an in-plane magnetic anisotropy in these samples.

Influence of Constant Magnetic Field on Domain Wall Dynamics in YFeO3

2017 ◽  
Vol 265 ◽  
pp. 636-639
Author(s):  
O.Yu. Komina ◽  
E.A. Zhukov
Keyword(s):  
Magnetic Field ◽  
Domain Wall ◽  
Constant Magnetic Field ◽  
Domain Walls ◽  
Domain Wall Motion ◽  
Sample Plane ◽  
Domain Wall Dynamics ◽  
Yttrium Orthoferrite ◽  
Oriented Parallel ◽  
Alternating Magnetic Fields

The work presents the experimental results of the dynamics of the domain wall in the plate of yttrium orthoferrite. In our case the speeds of this motion are much less than the speeds of sound in these crystals. A constant magnetic field was oriented parallel to the plate along the domain wall motion and at the angle ≈ 50° to the sample plane and parallel to the plate along the DW motion. We consider forced vibrations of the domain wall under the influence of weak alternating magnetic fields. The domain walls motion was caused by an alternating magnetic field, which was generated by the coils. The effect of the constant magnetic field on the domain wall dynamics has been found.

The direct determination of magnetic domain wall profiles using a split detector STEM

1978 ◽  
Vol 36 (1) ◽  
pp. 466-467
Author(s):  
J.N. Chapman ◽  
P.E. Batson ◽  
E.M. Waddell ◽  
R.P. Ferrier
Keyword(s):  
Electron Microscope ◽  
Domain Wall ◽  
Transmission Electron Microscope ◽  
Domain Walls ◽  
Photographic Plate ◽  
Magnetic Domain ◽  
Direct Determination ◽  
Quantitative Information ◽  
Scanning Transmission Electron Microscope ◽  
Transmission Electron

By far the most commonly used mode of Lorentz microscopy in the examination of ferromagnetic thin films is the Fresnel or defocus mode. Use of this mode in the conventional transmission electron microscope (CTEM) is straightforward and immediately reveals the existence of all domain walls present. However, if such quantitative information as the domain wall profile is required, the technique suffers from several disadvantages. These include the inability to directly observe fine image detail on the viewing screen because of the stringent illumination coherence requirements, the difficulty of accurately translating part of a photographic plate into quantitative electron intensity data, and, perhaps most severe, the difficulty of interpreting this data. One solution to the first-named problem is to use a CTEM equipped with a field emission gun (FEG) (Inoue, Harada and Yamamoto 1977) whilst a second is to use the equivalent mode of image formation in a scanning transmission electron microscope (STEM) (Chapman, Batson, Waddell, Ferrier and Craven 1977), a technique which largely overcomes the second-named problem as well.

The need of electron microscopy in the study of domains and domain walls in ferroelectrics

1994 ◽  
Vol 52 ◽  
pp. 550-551
Author(s):  
Wenwu Cao
Keyword(s):  
Domain Wall ◽  
Domain Walls ◽  
High Mobility ◽  
Continuum Theory ◽  
Polarization Vector ◽  
Ferroelectric Materials ◽  
Dielectric Constants ◽  
Nonlocal Coupling ◽  
Cubic Symmetry ◽  
Gradient Energy

Domain structures play a key role in determining the physical properties of ferroelectric materials. The formation of these ferroelectric domains and domain walls are determined by the intrinsic nonlinearity and the nonlocal coupling of the polarization. Analogous to soliton excitations, domain walls can have high mobility when the domain wall energy is high. The domain wall can be describes by a continuum theory owning to the long range nature of the dipole-dipole interactions in ferroelectrics. The simplest form for the Landau energy is the so called ϕ model which can be used to describe a second order phase transition from a cubic prototype,where Pi (i =1, 2, 3) are the components of polarization vector, α's are the linear and nonlinear dielectric constants. In order to take into account the nonlocal coupling, a gradient energy should be included, for cubic symmetry the gradient energy is given by,

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