Search results for "Single domain"
showing 9 items of 19 documents
Electrostatic model and NMR results for EFG tensors in tetragonal BaTiO3
1990
Abstract We present 47,49Ti and 135,137Ba NMR second-order quadrupolar rotation patterns in a tetragonal single domain crystal of BaTiO3. These data will be analysed in terms of a ionic polarizable point multipole model.
Magnetic Domain Structure and Intrinsic Magnetic Material Parameters of Ternary Intermetallic RMn2Ge2 Compounds (R ? La, Ce, Pr and Nd)
2000
Applying a powder pattern method the magnetic domain structures of polycrystalline intermetallic RMn2Ge2 (where R ≡ La, Ce, Pr, Nd) compounds were studied. The domain structures observed are typical for uniaxial materials. The domain wall energy density γ was determined from analysis of domain structure patterns, using different models of the domain structure. The obtained values are used to determine the intrinsic magnetic material parameters: domain wall width δB, critical diameters of single domain particles Dc and exchange constants A.
Scaling of intrinsic domain wall magneto-resistance with confinement in electromigrated nanocontacts
2018
In this work we study the evolution of intrinsic domain wall magnetoresistance (DWMR) with domain wall confinement. Clean permalloy notched half-ring nanocontacts are fabricated using a special ultra-high vacuum electromigration procedure to tailor the size of the wire in-situ and through the resulting domain wall confinement we tailor the domain wall width from a few tens of nm down to a few nm. Through measurements of the dependence of the resistance with respect to the applied field direction we extract the contribution of a single domain wall to the MR of the device, as a function of the domain wall width in the confining potential at the notch. In this size range, an intrinsic positive…
Local control of domain wall dynamics in ferromagnetic rings
2015
Ferromagnetic nanorings are of great interest due to prospective applications in memory and logic devices based on domain wall (DW) motion.1-3A key-prerequisite for their realization is a reproducible domain wall spin structure with a well-controllable wall velocity. We have found that DW propagation in magnetic ring is characterized by non-constant vortex DW velocity even below Walker breakdown4 (as opposed to straight wires). Several studies have been devoted to the optimization of ring reversal on a global scale using out-of plane field5 or flux charges emanating from neighboring rings if placed in close proximity6. However, these methods involve DW pinning and vortex nucleation processe…
Automotive domain wall propagation in ferromagnetic rings
2015
Automotive domain wall propagation is a self-propelling motion utilizing the energy stored in a particular energy reservoir of the spin structure to speed up domain wall beyond its equilibrium value given by external driving force and damping. Such a concept of DW motion is of great interest due to recent development of spintronic devices based on domain walls, where automotion could be used to assist or prevent domain wall pinning at low driving fields1-2. In turn, most of studies so far have been devoted to the automotion invoked by DW transformations from metastable to stable states3-4; appearing at sufficiently high magnetic fields strong and enough to trigger domain wall spin structure…
Dynamic domain wall chirality rectification by rotating magnetic fields
2015
We report on the observation of magnetic vortex domain wall chirality reversal in ferromagnetic rings that is controlled by the sense of rotation of a magnetic field. We use time-resolved X-ray microscopy to dynamically image the chirality-switching process and perform micromagnetic simulations to deduce the switching details from time-resolved snapshots. We find experimentally that the switching occurs within less than 4 ns and is observed in all samples with ring widths ranging from 0.5 μm to 2 μm, ring diameters between 2 μm and 5 μm, and a thickness of 30 nm, where a vortex domain wall is present in the magnetic onion state of the ring. From the magnetic contrast in the time-resolved im…
Dynamics of topological spin structures
2015
Topological spin structures that emerge from the Dzyaloshinskii-Moriya interaction (DMI), such as chiral domain walls and skyrmions have become the focus of intense investigations due to exciting physics and possible applications [1].
Anomalous behavior of the second magnetization peak inLa1.81Sr0.19CuO4single crystals: Possible influence of two-band superconductivity
2008
We report an anomalous temperature $T$ variation of the field ${H}_{\text{on}}$ for the onset of the second magnetization peak in ${\text{La}}_{1.81}{\text{Sr}}_{0.19}{\text{CuO}}_{4}$ single crystals with the external magnetic field $H$ oriented parallel to the $c$ axis. While the peak field ${H}_{p}$ has a continuous decrease with increasing $T$, ${H}_{\text{on}}$ exhibits a sudden decrease for $T\ensuremath{\sim}11--15\text{ }\text{K}$. This behavior appears to be related to the particular $T$ dependence of the superfluid density in the case of two-band superconductivity affecting the $T$ variation of the elastic energy of the vortex system at low $H$.
Controlled assembly of single colloidal crystals using electro-osmotic micro-pumps.
2017
We assemble charged colloidal spheres at deliberately chosen locations on a charged unstructured glass substrate utilizing ion exchange based electro-osmotic micro-pumps. Using microscopy, a simple scaling theory and Brownian Dynamics simulations, we systematically explore the control parameters of crystal assembly and the mechanisms through which they depend on the experimental boundary conditions. We demonstrate that crystal quality depends crucially on the assembly distance of the colloids. This is understood as resulting from the competition between inward transport by the electro-osmotic pump flow and the electro-phoretic outward motion of the colloids. Optimized conditions include sub…