Nonlinearity of Magnetostrictive Torque Sensor under Varying External Magnetic Field Strength

Correctly torquing bone screws is an important factor in achieving positive patient outcomes during orthopaedic surgery. A torque-limiting smart screwdriver concept has been proposed, and ongoing work is being undertaken to model the screwing process and allow the concept to work. These models require experimental validation, so a test rig was developed. The magnetostrictive torque sensor in this test rig was affected by magnetic parts of the test rig, which offset the zero-torque point; this raised concerns over the effects on linearity, which were tested here. The torque sensor was tested against a non-magnetostrictive reference under varying external magnetic conditions. While the magnetic field offset the torque, there was no notable change in linearity under the conditions tested, and the linearity was always within the datasheet specifications. Hence, we conclude that in the context of this test rig, there were no negative effects on linearity, although under higher loading or stronger magnetic conditions, this may not hold.

Geometrically Constrained Skyrmions

Skyrmions are chiral swirling magnetization structures with nanoscale size. These structures have attracted considerable attention due to their topological stability and promising applicability in nanodevices, since they can be displaced with spin-polarized currents. However, for the comprehensive implementation of skyrmions in devices, it is imperative to also attain control over their geometrical position. Here we show that, through thickness modulations introduced in the host material, it is possible to constrain three-dimensional skyrmions to desired regions. We investigate skyrmion structures in rectangular FeGe platelets with micromagnetic finite element simulations. First, we establish a phase diagram of the minimum-energy magnetic state as a function of the external magnetic field strength and the film thickness. Using this understanding, we generate preferential sites for skyrmions in the material by introducing dot-like “pockets” of reduced film thickness. We show that these pockets can serve as pinning centers for the skyrmions, thus making it possible to obtain a geometric control of the skyrmion position. This control allows for stabilization of skyrmions at positions and in configurations that they would otherwise not attain. Our findings may have implications for technological applications in which skyrmions are used as units of information that are displaced along racetrack-type shift register devices.

Spin-Polarized Current-Driven Ferromagnetic Domain Wall Motion with a Skyrmion-Like Building Block

The purpose of the research is the construction of an analytic model for the description of a spin-polarized current-driven ferromagnetic domain wall motion with a skyrmion-like building block. The motion velocity of the ferromagnetic domain wall with a skyrmion-like building block is found as a function of the driving torques and an external magnetic field strength.

Thermodynamic properties of a spin-1 model with long-range interactions

The long-range interacting spin-1 chain placed in a staggered magnetic field is studied by means of microcanonical approach. Firstly, we study the microcanonical entropy of the system in the thermodynamic limit and find the system is non-ergodic and can exhibit either first-order phase transition or second-order phase transition by shifting the external magnetic field strength. Secondly, we construct the global phase diagram of the system and find a phase transition area in the phase diagram corresponding to the temperature jump of the first-order phase transition.

The Effect of Low-Intensity Static Magnetic Field on Ni-P-PTFE Electroless Composite Plating Coatings

A new processing concept has been developed to produce Ni-P-PTFE electroless composite coating. This method combines magnetic field and electroless composite plating techniques to prepare high-quality Ni-P-PTFE electroless composite coating. The influence of magnetic on composite plating process and coatings performance by changing some factors such as the plating time, magnetic field strength, magnetic field direction. The results indicate that the external magnetic field improved deposition rate and the PTFE particles content of composite coatings, meanwhile, some performances of composite coating like thickness, corrosion resistance, were effected by external magnetic field strength. Therefore, the method combines magnetic field and electroless completing techniques had a wide application prospect in the aspect of improving the properties of electroless composite coating.

Unveiling the thermal entanglement in a mixed-spin XXZ model with Dzyaloshinskii–Moriya interaction under a homogeneous magnetic field

We analytically investigate the thermal entanglement of three-mixed-spin (1/2, 1, 1/2) XXZ model with the DM interaction under an external magnetic field B. Two different cases are considered: one subsystem (1/2, 1/2) consists of two spin-1/2 fermions and the other subsystem (1/2, 1) contains a spin-1/2 fermion and a spin-1 boson. It is shown that the DM interaction parameter D, the external magnetic field strength B and coupling constant J have different effects on Fermi and mixed Fermi–Bose systems. All of the factors mentioned above can be utilized to control entanglement switch of any two particles in mixed spins model.

Compressional magnetoacoustic waves in a quantum dusty magnetoplasma

The linear dispersion relation for compressional magnetoacoustic waves in a quantum magnetoplasma is derived, taking into account the quantum Bohm potential and the magnetization of electrons due to the electron-1/2 spin effect. It is found that the quantum forces produce the wave dispersion at quantum scales, which depend on the external magnetic field strength.