Fabrication and Magnetic Behavior of Jellyfish-Like Ni Nanowires Synthesized Using Bilayered Nanoporous Anodic Alumina Templates.

The potential to produce nanostructures with intricate shapes in large quantities holds promise for a range of applications in the fields of nanoelectronics and biomedicine. Here a method for fabricating jellyfish-like Ni nanowires (JFNWs) using bilayered nanoporous anodic alumina templates with through pores of varying diameters in each layer is presented. To assess the capabilities of this method, samples are created with different voltages during the second step of anodization, resulting in distinct geometrical characteristics of the second layer of the template, and subsequently synthesize Ni JFNWs.

Microstructure, ion adsorption and magnetic behavior of mesoporous γ-FeO ferrite nanoparticles.

Magnetic nanoparticles with capacity for surface functionalisation have potential applications in water purification and biomedicine. Here, a simple co-precipitation technique was used to synthesize mesoporous ferrite nanoparticles in the presence of cetyltrimethylammonium bromide (CTAB) micellular surfactant. The as-synthesized ferrite nanoparticles were calcined at 250 °C for 5, 10, 15, and 24 h to remove the surfactant and create a mesoporous structure.

Nonuniform Current-Driven Formation and Displacement of the Magnetic Compensation Point in Variable-Width Nanoscale Ferrimagnets.

Nano- and microstructures based on ferrimagnets can demonstrate high efficiency and dynamics of current-induced magnetization switching combined with high stability of spin textures such as bubble domains and skyrmions, which are of practical importance for the development of spintronics and spin-orbitronics. This set of features is usually associated with magnetic momentum or angular momentum compensation states. Here, we experimentally show that the compensation state can be realized locally using nonuniform Joule heating.

Electronic Structure of NdFeCoB Oxide Magnetic Particles Studied by DFT Calculations and XPS.

Neodymium-iron-boron magnetic oxide powders synthesized by sol-gel Pechini method were studied by using X-ray photoelectron spectroscopy (XPS) and quantum chemical modeling. The powder structure was examined by using X-ray diffraction (XRD) and modeled by using density functional theory (DFT) approximation. The electronic structures of the core and valent regions were determined experimentally by using X-ray photoelectron spectroscopy and modeled by using quantum chemical methods.

Interwire and Intrawire Magnetostatic Interactions in Fe-Au Barcode Nanowires with Alternating Ferromagnetically Strong and Weak Segments.

Metallic barcode nanowires (BNWs) composed of repeating heterogeneous segments fabricated by template-assisted electrodeposition can offer extended functionality in magnetic, electrical, mechanical, and biomedical applications. The authors consider such nanostructures as a 3D system of magnetically interacting elements with magnetic behavior strongly affected by complex magnetostatic interactions. This study discusses the influence of geometrical parameters of segments on the character of their interactions and the overall magnetic behavior of the array of BNWs having alternating magnetization, because the Fe and Au segments are made of Fe-Au alloys with high and low magnetizations.

Field-Free Spin-Orbit Torque Switching Enabled by the Interlayer Dzyaloshinskii-Moriya Interaction.

Perpendicularly magnetized structures that are switchable using a spin current under field-free conditions can potentially be applied in spin-orbit torque magnetic random-access memory (SOT-MRAM). Several structures have been developed; however, new structures with a simple stack structure and MRAM compatibility are urgently needed. Herein, a typical structure in a perpendicular spin-transfer torque MRAM, the Pt/Co multilayer and its synthetic antiferromagnetic counterpart with perpendicular magnetic anisotropy, was observed to possess an intrinsic interlayer chiral interaction between neighboring magnetic layers, namely, the interlayer Dzyaloshinskii-Moriya interaction (DMI) effect.

Field-free superconducting diode effect in noncentrosymmetric superconductor/ferromagnet multilayers.

The diode effect is fundamental to electronic devices and is widely used in rectifiers and a.c.-d.

XMCD and study of interface-engineered ultrathin Ru/Co/W/Ru films with perpendicular magnetic anisotropy and strong Dzyaloshinskii-Moriya interaction.

Understanding the nature of recently discovered spin-orbital induced phenomena and a definition of a general approach for "ferromagnet/heavy-metal" layered systems to enhance and manipulate spin-orbit coupling, spin-orbit torque, and the Dzyaloshinskii-Moriya interaction (DMI) assisted by atomic-scale interface engineering are essential for developing spintronics and spin-orbitronics. Here, we exploit X-ray magnetic circular dichroism (XMCD) spectroscopy at the -edges of 5d and 4d non-magnetic heavy metals (W and Ru, respectively) in ultrathin Ru/Co/W/Ru films to determine their induced magnetic moments due to the proximity to the ferromagnetic layer of Co. The deduced orbital and spin magnetic moments agree well with the theoretically predicted values, highlighting the drastic effect of constituting layers on the system's magnetic properties and the strong interfacial DMI in Ru/Co/W/Ru films.

FORC-Diagram Analysis for a Step-like Magnetization Reversal in Nanopatterned Stripe Array.

The fabrication approach of a magnonic crystal with a step-like hysteresis behavior based on a uniform non-monotonous iron layer made by shadow deposition on a preconfigured substrate is reported. The origin of the step-like hysteresis loop behavior is studied with local and integral magnetometry methods, including First-Order Reversal Curves (FORC) diagram analysis, accompanied with magnetic microstructure dynamics measurements. The results are validated with macroscopic magnetic properties and micromagnetic simulations using the intrinsic switching field distribution model.

Current-Induced Manipulation of the Exchange Bias in a Pt/Co/NiO Structure.

An experimental study of the phenomenon of electric current influence on the value and orientation of the exchange bias field () in the Pt/Co/NiO structure is carried out. Depending on the direction of the magnetization in a ferromagnet (FM) layer and the current pulse amplitude, the value of the field can be changed repeatedly in the range of ±7.5 mT.

Ruderman-Kittel-Kasuya-Yosida-type interfacial Dzyaloshinskii-Moriya interaction in heavy metal/ferromagnet heterostructures.

The manipulation of magnetization with interfacial modification using various spin-orbit coupling phenomena has been recently revisited due to its scientific and technological potential for next-generation memory devices. Herein, we experimentally and theoretically demonstrate the interfacial Dzyaloshinskii-Moriya interaction characteristics penetrating through a MgO dielectric layer inserted between the Pt and CoFeSiB. The inserted MgO layer seems to function as a chiral exchange interaction mediator of the interfacial Dzyaloshinskii-Moriya interaction from the heavy metal atoms to ferromagnet ones.

Skyrmionium - high velocity without the skyrmion Hall effect.

The lateral motion of a magnetic skyrmion, arising because of the skyrmion Hall effect, imposes a number of restrictions on the use of this spin state in the racetrack memory. A skyrmionium is a more promising spin texture for memory applications, since it has zero total topological charge and propagates strictly along a nanotrack. Here, the stability of the skyrmionium, as well as the dependence of its size on the magnetic parameters, such as the Dzyaloshinskii-Moriya interaction and perpendicular magnetic anisotropy, are studied by means of micromagnetic simulations.

Magnetization reversal of ferromagnetic nanosprings affected by helical shape.

Helicity, a natural property of macro-, micro-, and nano-objects, potentially offers a new dimension to mechanical and electromagnetic applications for creating emerging nanodevices, such as nanorobots, nanomagnets, nanosensors, and high-density magnetic memory. Helical magnetic nanosprings are unique objects with remarkable magnetic properties, including the absence of stray fields in remanence owing to the chiral geometry, which makes them promising for data storage devices, nanoelectromechanical systems, and biomedical usage. Here, we investigated Co and CoFe nanospring arrays electrodeposited in highly ordered nanoporous templates.

Fabrication of high-resolution nanostructures of complex geometry by the single-spot nanolithography method.

The paper presents a method for the high-resolution production of polymer nanopatterns with controllable geometrical parameters by means of a single-spot electron-beam lithography technique. The essence of the method entails the overexposure of a positive-tone resist, spin-coated onto a substrate where nanoscale spots are exposed to an electron beam with a dose greater than 0.1 pC per dot.

Manipulation of magnetic vortex parameters in disk-on-disk nanostructures with various geometry.

Magnetic nanostructures in the form of a sandwich consisting of two permalloy (Py) disks with diameters of 600 and 200 nm separated by a nonmagnetic interlayer are studied. Magnetization reversal of the disk-on-disk nanostructures depends on the distance between centers of the small and big disks and on orientation of an external magnetic field applied during measurements. It is found that manipulation of the magnetic vortex chirality and the trajectory of the vortex core in the big disk is only possible in asymmetric nanostructures.