We investigate the Dzyaloshinskii-Moriya interactions (DMIs) in perpendicularly magnetized thin films of Pt/Co/Pt and Pt/Co/Ir/Pt. To study effective DMI, arising at either side ferromagnet, we use a field-driven domain wall creep-based method. The only magnetic field removes possibility mixing with current-related effects such as spin Hall effect or Rashba field, well complexity from lithographic patterning. Inserting an ultrathin layer Ir top Co/Pt interface allows us to access DMI...

We report on domain wall pinning behavior and the potential-energy landscapes created by notches of two different geometries in planar Permalloy nanowires. Domain depinning was probed experimentally using spatially resolved magneto-optical Kerr effect measurements. The spin structure pinned walls determined Lorentz microscopy, also analyzed micromagnetic simulations, which are good qualitative agreement with experimental results. All notch structures have dimensions that comparable length...

Abstract The microscopic magnetization variation in magnetic domain walls thin films is a crucial property when considering the torques driving their dynamic behaviour. For possessing out-of-plane anisotropy normally presence of Néel not favoured due to magnetostatic considerations. However, they have right structure respond exerted by spin Hall effect. Their existence an indicator interfacial Dzyaloshinskii–Moriya interaction (DMI). Here we present direct imaging with fixed chirality...

The application of differential phase contrast imaging to the study polycrystalline magnetic thin films and nanostructures has been hampered by strong diffraction resulting from granular structure materials. In this paper we demonstrate how a pixelated detector used detect bright field disk in aberration corrected scanning transmission electron microscopy (STEM) subsequent processing acquired data allows efficient enhancement images. Initial results charged coupled device (CCD) camera highly...

Theoretical analysis and Lorentz transmission electron microscopy (LTEM) investigations in an FeGe wedge demonstrate that chiral twists arising near the surfaces of noncentrosymmetric ferromagnets [Meynell et al., Phys. Rev. B 90, 014406 (2014)] provide a stabilization mechanism for magnetic Skyrmion lattices helicoids cubic helimagnet nanolayers. The phase diagram obtained freestanding nanolayers shows magnetization processes differ fundamentally from those bulk helimagnets are...

Understanding the conditions determining appearance of stable chiral spin topological excitations is a central problem in condensed matter physics and related fields. This work provides first unambiguous demonstration discretization due to macroscopic phase coherence metastability for excitations, evidence mechanisms underlying its appearance. was achieved through use an advanced Lorentz electron microscope with highest possible resolution imaging textures. The results provide new insights...

Chirality plays a major role in nature, from particle physics to DNA, and its control is much sought-after due the scientific technological opportunities it unlocks. For magnetic materials, chiral interactions between spins promote formation of sophisticated swirling states such as skyrmions, with rich topological properties great potential for future technologies. Currently, magnetism requires either restricted group natural materials or synthetic thin-film systems that exploit interfacial...

The design of complex, competing effects in magnetic systems-be it via the introduction nonlinear interactions1-4, or patterning three-dimensional geometries5,6-is an emerging route to achieve new functionalities. In particular, through geometries and curvature, intrastructure properties such as anisotropy chirality, both geometry-induced intrinsic, can be directly controlled, leading a host physics functionalities, chiral spin states7, ultrafast domain wall dynamics8-10 textures with...

A modification to the differential phase contrast mode of Lorentz microscopy is proposed in which an annular quadrant detector used instead standard solid detector. The new imaging allows a high degree control over relative efficiencies with low and spatial frequency information can be transferred from specimen image. This makes it possible effect considerable separation arising magnetic nonmagnetic origins thin polycrystalline films thus reveals finer detail than was hitherto possible....

A novel transmission electron microscope optimised for the study of magnetic material is described. Using this instrument, a new method revealing structures, coherent Foucault imaging, can be realised. Images appear directly in form interferograms and provide immediate access to quantitative description induction distribution across specimen. simple analytical approach given underlying theory main features are confirmed by computer modelling. Experimental images small regular permalloy...

Abstract We have imaged Néel skyrmion bubbles in perpendicularly magnetised polycrystalline multilayers patterned into 1 µm diameter dots, using scanning transmission x-ray microscopy. The can be nucleated by the application of an external magnetic field and are stable at zero with a 260 nm. Applying out plane that opposes magnetisation bubble core moment applies pressure to gradually compresses it approximately 100 On removing returns its original via hysteretic pathway where most expansion...

Abstract The knowledge of how magnetization looks inside a ferromagnet is often hindered by the limitations available experimental methods which are sensitive only to surface regions or limited in spatial resolution. Here we report vector tomographic reconstruction based on soft X-ray transmission microscopy and magnetic dichroism data, has allowed visualizing three-dimensional ferromagnetic thin film heterostructure. Different non-trivial topological textures have been resolved...

Differential phase contrast (DPC) imaging in the scanning transmission electron microscope is applied to study of a charged antiphase domain boundary doped bismuth ferrite. A clear differential signal seen, which matches expected direction electric field at boundary. However, further by scanned diffraction reveals that there no measurable deflection primary disc and hence significant free E-field material. Instead, DPC arises from modulation intensity profile within vicinity Simulations are...

We have utilised a high spatial resolution imaging method, Differential Phase Contrast (DPC) performed in scanning transmission electron microscope (STEM), for precise measurement of the magnetic induction distribution skyrmion states noncentrosymmetric magnetically ordered materials. Applied to investigate internal structure hexagonal lattice cells, stabilised by an out-plane applied field FeGe nanowedge specimen, mapping in-plane component has yielded "average" profiles and observation...

Amorphous zirconium oxide thin films deposited at room temperature, sandwiched between Pt and Ti electrodes, show resistive bipolar switching with good overall performance figures (retention, ON/OFF ratio durability). A variability observed during electrical characterisation is consistent the coexistence of two different mechanisms within ZrO2 layer. Electron energy loss spectroscopy used to map chemical variations across device on nanoscale. Partial oxidation electrode creates an ohmic...

Skyrmions in ultrathin ferromagnetic metal (FM)/heavy (HM) multilayer systems produced by conventional sputtering methods have recently generated huge interest due to their applications the field of spintronics. The sandwich structure with two correctly-chosen heavy layers provides an additive interfacial exchange interaction which promotes domain wall or skyrmion spin textures that are Néel character and a fixed chirality. Lorentz transmission electron microscopy (TEM) is high resolution...

Two different lithographic techniques have been developed for fabricating magnetic nano-elements on ultra-thin electron-transparent substrates thereby allowing transmission electron microscopy to be used investigate their properties. Here we describe studies of elements micropolycrystalline Permalloy and cobalt whose thicknesses lie in the range 20-30 nm. Bright field images show that a high degree edge acuity is attained with lateral dimensions /spl ap/25 nm produced. Lorentz has provided...

The stability of the asymmetric domain wall (ATDW) in soft magnetic cylindrical nanowires and nanotubes is investigated using micromagnetic simulations. Our calculated phase diagram shows that for permalloy nanowires, transverse (TDW) ground state radii below 20 nm whilst Bloch point (BPW) favoured thicker wires. ATDW stabilises only as a metastable but with energy close to BPW. Characterisation DW spin structures reveals has vortex-like surface state, contrast divergent spins TDW. This...

Using Lorentz transmission electron microscopy and small-angle scattering techniques, we investigate the temperature-dependent evolution of a magnetic stripe pattern period in thin-film lamellae prototype monoaxial chiral helimagnet ${\mathrm{CrNb}}_{3}{\mathrm{S}}_{6}$. The sinusoidal appears due to formation helimagnetic order (CHM) this material. We found that as temperature increases, CHM is initially independent then starts shrink above about 90 K, which far below phase transition for...

Magnetic skyrmions are particle-like deformations in a magnetic texture. They have great potential as information carriers spintronic devices because of their interesting topological properties and favorable motion under spin currents. A new method nucleating at nanoscale defect sites, created controlled manner with focused ion beam irradiation, polycrystalline multilayer samples an interfacial Dzyaloshinskii-Moriya interaction, is reported. This has three notable advantages: 1) localization...

The cross-integration of spin-wave and superconducting technologies is a promising method for creating novel hybrid devices future information processing to store, manipulate, or convert data in both classical quantum regimes. Hybrid magnon-polariton systems have been widely studied using bulk Yttrium Iron Garnet (Y$_{3}$Fe$_{5}$O$_{12}$, YIG) three-dimensional microwave photon cavities. However, limitations YIG growth thus far prevented its incorporation into CMOS compatible technology such...

In synthetic antiferromagnets (SAFs), antiferromagnetic (AFM) order and synthesis using conventional sputtering techniques is combined to produce systems that are advantageous for spintronics applications. Here we present the preparation study of SAF multilayers possessing both perpendicular magnetic anisotropy Dzyaloshinskii-Moriya interaction. The have an antiferromagnetically aligned ground state but can be forced into a full ferromagnetic (FM) alignment by applying out-of-plane field...

We have investigated the magnetic properties of ultra-small-patterned elements Co and NiFe thin films. The were rectangular with an aspect ratio in range 3.75–20. smallest 200×40 nm2 50 nm gaps between them, corresponding to areal density 27 Gbit/in2 if used as discrete-patterned media for recording. fabricated by electron-beam lithography lift-off patterning high-resolution images obtained Lorentz microscopy a transmission electron microscope. In situ magnetization reversal experiments...