3D print is a recently developed technique, for single-unit production, and structures that have been impossible to build previously. The current work presents method polymer bonded isotropic hard magnets with low-cost, end-user printer. Commercially available NdFeB powder inside PA11 matrix characterized, prepared the printing process. An example of printed magnet complex shape was designed generate specific stray field presented, compared finite element simulation solving macroscopic...

Additive manufacturing of polymer bonded magnets is a recently developed technique, for single-unit production, and structures that have been impossible to manufacture previously. Also new possibilities create specific stray field around the magnet are triggered. The current work presents method 3D print with variable magnetic compound density distribution. A low-cost, end-user printer mixing extruder used mix permanent filaments pure PA12 filaments. compounded, extruded, characterized...

The limits of areal storage density that is achievable with heat-assisted magnetic recording are unknown. We addressed this central question and investigated the bit-patterned media. analyzed detailed switching behavior a bit under various external conditions, allowing us to compute error rate write process (shingled conventional) for grain spacings, head positions, temperatures. Hence, we were able optimize yielding values beyond 10 Tb/in2. Our model based on Landau-Lifshitz-Bloch equation...

Topology optimization offers great opportunities to design permanent magnetic systems that have specific external field characteristics. Additive manufacturing of polymer bonded magnets with an end-user 3D printer can be used manufacture structures been difficult or impossible previously. This work combines these two powerful methods and system properties. The topology framework is simple, fast, accurate. It also for reverse engineering in order find the from measurements. Furthermore, a...

Abstract We solve a time-dependent three-dimensional spin-diffusion model coupled to the Landau-Lifshitz-Gilbert equation numerically. The presented is validated by comparison two established spin-torque models: of Slonzewski that describes in multi-layer structures presence fixed layer and Zhang Li current driven domain-wall motion. It shown both models are incorporated description, i.e., nonlocal effects captured as well spin-accumulation due magnetization gradients described Li. Moreover,...

Skyrmions and antiskyrmions are topologically protected spin structures with opposite topological charge. Particularly in coexisting phases, these two types of magnetic quasi-particles may show fascinating physics potential for spintronic devices. While skyrmions observed a wide range materials, until now were exclusive to materials D2d symmetry. In this work, we first second-order stabilized by dipole-dipole interaction Fe/Gd-based multilayers. We modify the properties multilayers Ir...

We propose a three-dimensional micromagnetic model that dynamically solves the Landau-Lifshitz-Gilbert equation coupled to full spin-diffusion equation. In contrast previous methods, we solve for magnetization dynamics and electric potential in self-consistent fashion. This treatment allows an accurate description of dependent resistance changes. Moreover, presented algorithm describes both spin accumulation due smooth transitions material interfaces as multilayer structures. The its...

Abstract In this paper, the thermal stability of skyrmion bubbles and critical currents to move them over pinning sites were investigated. For used geometries parameters, unexpected behavior is reported that energy barrier overcome site larger than annihilation a skyrmion. The takes place at boundaries by current driven motion, as well due excitation barriers, in absence currents, without forming Bloch points. It sites, which are required allow thermally stable bits, significantly increase...

<title>Abstract</title> This work provides a complete numeric framework, with which soft magnetic composite-materials can be numerically analyzed through combination of two distinct numerical methods. Key properties connected to energy efficiency, namely the permeability and energy-loss predicted. The latter consists different contributions. These contributions are treated separately in our therefore 2 decoupled models required fully encompass these materials. Experimentally established...

Polycrystalline Nickel-Zinc (NiZn) ferrites are widely utilized in high-frequency applications due to their excellent magnetic properties, including high resistivity, low power losses, and permeability. However, data on loss behavior at 10 MHz, particularly elevated temperatures, remain limited the literature. This study investigates performance of NiZn under varying induction fields (3–10 mT) temperatures (20–120°C), with a focus reducing high-temperature losses. Ferrite samples were...

Heat assisted recording is a promising technique to further increase the storage density in hard disks. Multilayer grains with graded Curie temperature discussed assist write process. Describing correct magnetization dynamics of these grains, from room far above point, during process required for calculation bit error rates. We present coarse grained approach based on Landau-Lifshitz-Bloch (LLB) equation model exchange coupled low computational effort. The dependent material properties such...

We perform a direct comparison between Kramers' method in many dimensions -- i.e., Langer's theory adapted to magnetic spin systems, and path sampling the form of forward flux sampling, as means compute collapse rates metastable skyrmions. show that good agreement is obtained two methods. report variations attempt frequency associated with skyrmion by three four orders magnitude when varying applied field 5$\%$ exchange strength, which confirms existence strong entropic contribution lifetime...

The switching probability of magnetic elements for heat assisted recording is investigated. It found that FePt with a diameter 5 nm and height 10nm show, at field 0.5 T, thermally written in errors 12 percent, which significant too large bit patterned recording. Thermally can be decreased if larger head fields are applied. However, lead to an increase the fundamental thermal jitter. This leads dilemma between partly relaxed by increasing thickness film up 30nm. For realistic fields, it...

Abstract An efficient algorithm for the reconstruction of magnetization state within magnetic components is presented. The occurring inverse magnetostatic problem solved by means an adjoint approach, based on Fredkin-Koehler method solution forward problem. Due to use hybrid FEM-BEM coupling combined with matrix compression techniques resulting well suited large-scale problems. Furthermore a permanent magnet as optimal design application are demonstrated.

Spin-transfer-torque magnetoresistive random-access memory (STT-MRAM) is a very promising approach to ultralow-power, nonvolatile storage devices. While prototypes are already being manufactured, known problem with this technology ``back-hopping'' (undesired high-frequency switching) in the information-carrying layer during writing. The authors investigate destabilization of reference as possible origin back-hopping, and propose measures avoid it. Device miniaturization will increase impact...

Heat-assisted-magnetic recording (HAMR) is hoped to be the future technique for high density storage devices. Nevertheless, there exist several realizations strategies. With a coarse-grained Landau-Lifshitz-Bloch (LLB) model we investigate in detail benefits and disadvantages of continuous pulsed laser spot shingled conventional bit-patterned media. Additionally compare single phase grains bits having bilayer structure with graded Curie temperature, consisting hard magnetic layer...

Artificial kagome spin ice exhibits exotic magnetic correlations driven by a combination of geometric frustration and dipolar interactions that, at low-enough temperature, can result in ordered phases. This order, whether it is the ground state several rings, or theoretically predicted long-range order an extended array, has yet to be experimentally observed. By introducing interfacial Dzyaloshinskii-Moriya interaction, we are able reduce blocking temperature individual nanomagnets, allowing...

A low cost passive wireless strain sensor is proposed. The basis of the formed by two softmagnetic magnetostrictive ribbons. first ribbon transforms mechanical stress into a dependent magnetic field. second senses this field magnetoacoustic oscillations. resonance frequency directly depends on applied stress. For proposed sensor, gauge factor Gf, which defined as relative change divided ɛ, Gf = 380 obtained. This significantly higher than standard metal foil gages.

We present an analytical derivation of the switching field distribution (SFD) at finite temperature for a single domain particle from Néel-Brown model in presence linearly swept magnetic field. By considering dependence attempt frequency f0 rate equation, we find enhancement coercivity compared to models using constant f0. The contribution thermal fluctuations standard deviation HC derived here reaches values 10% HC. Considering this contribution, which has been neglected previous work, is...

Predicting the thermal stability of magnetic storage devices is an important and challenging task. Here, we demonstrate how forward flux sampling method (FFS) can be used to determine magnets with general microstructures for time scales ranging from picoseconds years. To apply FFS systems, first use nudged elastic band (NEB) a minimum energy path connecting initial final state transition. Interfaces defined based on this then provide basis procedure in which dynamical trajectories are...

We investigate the spin-transfer torque in a magnetic multilayer structure by means of spin-diffusion model. The considered system, consisting two layers separated conducting layer, is caused perpendicular-to-plane current. compute strength field-like and damping-like for different material parameters geometries. Our studies suggest that highly depends on exchange coupling itinerant electrons with magnetization both pinned free layer. While low leads to very high torques, or even negative...

A skyrmion racetrack design is proposed that allows for thermally stable skyrmions to code information and dynamical pinning sites move with the applied current. This concept solves problem of intrinsic distributions times currents at static due geometrical constrictions or disordered film. The are realized by a carrying wire, where repulsion used in order keep equal distances. coded an additional layer presence absence information. lowest energy barrier data loss calculated be ΔE = 55...