In this work, we consider a topological Josephson junction that contains conventional superconductors and ferromagnet leads on the surface of three-dimensional topological insulators. We use Bogoliubov-deGennes formalism to show in-plane magnetization with a component perpendicular to the superconductor interface that alters the Andreev bound states and creates an Andreev zone. This effect reduces the magnitude of the supercurrent. Also, magnetization changes the spin arrangement of surface states and creates spin-polarized supercurrent. Because of strong spin-momentum interaction on topological insulators, the spin-polarized supercurrent has in-plane components with maximum value in m_x~Δ_0⁄2. On the other hand, the parallel component of in-plane magnetization creates an anomalous supercurrent that flows in the absence of a superconducting phase difference. The dissipation-less spin-polarized supercurrent has great importance from the application point of view in designing spintronics devices.

Charge creation in superconductor layers affects current–voltage characteristics (CVC) of the Josephson junction array and creates a breakpoint region in CVC. This charge may oscillate in the form of longitudinal plasma wave, (LPW), or nonregularity. In this paper we intend to distinguish the region with LPW from the nonregular region.

he Josephson Fluxonic Diode is a long Josephson junction that uses oppositely directed magnetic flux quanta, associated with current votrices and antivortices, as its basis operation. the movement of the vortices creates a changing phase. this in turn creates a voltage drop. in this paper, discrete JJ is proposed instead of continues JJ in JFD. Also, by numerical calculation of the discrete sine-Gordon equation, the manner of the carriers is discussed in discrete JJ. Numerically study of the dynamics of JFD based on discrete JJ shows a rectification. Because of it is easy to adjust the value of the junction parammeters, and it is possible to have single flux quantum stuffed in a small area by adjusting the discreetness parameter, it is expected that the useful and practical Josephson fluxonic devices can be made by discrete JJs.

The Josephson junction is a device consisting of two superconducting electrodes connected by a weak junction such as a thin insulation coating. The Josephson junction has chaotic behavior parameters not desirable in high-frequency applications. In this paper, a model predictive control approach based on an ant colony optimization algorithm is proposed to synchronize two Josephson junction models with different parameters. Here, the Josephson junction is described with a nonlinear model, and the synchronization is obtained using the slave–master technique. For this purpose, an appropriate objective function is defined to assess the particles within the state space. This objective function minimizes simultaneously the tracking error, control effort, and control smoothness. The dynamic optimization problem is solved using an ant colony optimization algorithm. Numerical simulations are conducted to assess the efficiency of the proposed algorithm. Also, a Monte Carlo evaluation is achieved to compute the statistic performance of the suggested controller. In addition, sensitivity analysis to changes in the number of ants and the number of iteration of the inner loop of the algorithm was performed. The results show that the controller is significantly sensitive to reducing the number of iteration of the inner loop.

In this paper, a model predictive control approach based on a generic particle filter is proposed to synchronize two Josephson junction models with different parameters. For this purpose, an appropriate objective function is defined to assess the particles within the state space. This objective function minimizes simultaneously the tracking error, control effort, and control smoothness. The dynamic optimization problem is solved using a generic particle filter. Here, Josephson junction is described with Resistive Capacitive Inductive Shunted Josephson model, and the synchronization is obtained using the slave–master technique. Moreover, to verify the implementation capability of the proposed algorithm, a processor in loop experiment is performed. The results show that the open-loop system, without the controller, has a chaotic behavior. Numerical simulations are conducted to assess the performance of the proposed algorithm. The results show that the proposed approach can be implemented in a real-time application. Also, the performance of the suggested controller is compared with the proportional integral derivative controller and sliding mode controller.

An investigation of the modern phenomena of condensed matter physics, called, magnetization plateau and magnetization jump, visible as anomalies in spin susceptibility at zero temperature, have been carried out theoretically in a zero-dimensional boron triangular Kagome lattice (0D-BTKL), namely quantum dots of BTKL, subjected to a staggering sublattice potential. By analyzing the Ruderman-Kittel-Kasuya-Yoshida (RKKY) interaction, the magnetic ground state of the 0D-TKL in the presence of two magnetic adatoms, in the presence of a staggered sublattice potential is evaluated. The important salient feature of the 0D-BTKLs is the emergence of the RKKY plateaus versus the Fermi energy. The spatial configurations of the magnetic impurities dramatically change the quality and quantity of the RKKY plateaus. These RKKY plateaus have not been reported before, to the best of our knowledge. Our finite-size results successfully confirm that both the width and location of the RKKY plateaus are tunable using an external potential and Fermi energy. Another remarkable observation is the nontrivial behavior, namely the magnetization jump, which accompanies the discontinuity in the spin susceptibility curves versus the staggering potential in our calculations. We believe that our results provide significant insights towards designing further experiments to search for the realization of the magnetization plateau phases and magnetization jumps in spintronics and pseudospin electronics devices based on BTKLs.

Superparamagnetic nanoparticles with high saturation magnetism and small average size were synthesized by the economic co-precipitation method. FeCl2.4H2O and FeCl3.6H2O were used as salt agents and NaOH as precipitant. Different reaction conditions were investigated to improve the saturation magnetization of synthesized magnetic nanoparticles by adjusting the reactants' concentration and the reaction's temperature. The magnetic and structural properties of the synthesized nanoparticles were investigated by XRD and VSM, respectively. magnetization curves were analyzed to calculate the size of the magnetic moment of nanoparticles and saturation magnetization. For each sample, three mean magnetic sizes were estimated by employing the region of the curve in the small limit, high limit, and both small and high limits of applied magnetic fields. Their sizes were also estimated by using the Scherrer formula. The mean magnetic size estimated using the region of small applied fields was in agreement with that estimated by the Scherrer formula. Although both saturation magnetization and the size of prepared nanoparticles were increased with reaction temperature, the saturation magnetization of nanoparticles was enhanced from 56 to 85 emu/g. In contrast, their mean magnetic size changed only between 7 to 12 nm.

Interoduction: We consider the 1D spin-1/2 quantum compass model. At zero temperature, the behavior of the system is in the rule of quantum fluctuations. At this temperature, the model on the critical line is considered and a transverse magnetic field is applied. Using the numerical Lanczos method the ground state of the system and magnetization for chains up to 20 spins is calculated. We have showed the depend on the exchange couplings the magnetization remains zero up to a critical magnetic field. At high magnetic field the magnetization saturate.Aim: Effects of transverse magnetic field in the quantum compass model has been investigated.Material and Method: In order to study the ground state properties of the system we have used Lanczos numerical method.Results: It has been shown that implementing transverse magnetic field causes to increase magnetization slowly till a point which magnetization reach its saturation value.Conclusion: With increasing transverse magnetic field in the quantum compass model, magnetization will increase gradually up to a saturation value.

A tight binding approach based on the Bogoliubov de-Genes approach has been used to calculate the DC Josephson current for short junctions with respect to the superconducting coherence length with a lattice model for SGNR-S junctions. We calculate the phase, length, width, and chemical potential dependence at the Josephson junction and discuss the similarities and differences with regard to the theoretical and experimental results obtained for graphene. Regarding the calculations on graphene, using a lattice model, we convert the graphene honeycomb structure to a brick lattice structure that does not change the lattice topology. Then, by removing several atoms from the lattice, we create the simple vacancy defects in the brick lattice. Also we calculate the Josephson current with these vacancies.