In the present study, the MAGNETIC properties of three-dimensional TOPOLOGICAL INSULATORS, doped with MAGNETIC atoms are investigated. The spin-orbit locking of surface electrons results in interesting MAGNETIC behaviors, absent in conventional INSULATORS without spin-orbit coupling. One of these behaviors is the strong dependence of ferroMAGNETIC paraMAGNETIC transition temperature on different system parameters. Here, using the mean-field formalism, we have studied the effects of hexagonal warping on the order parameter, critical temperature, and MAGNETIC susceptibility of system.

TOPOLOGICAL INSULATORS are systems where the broken time reversal symmetry gives rise to protected edge modes that support backscatter-free and one-way propagation of electroMAGNETIC waves by opening non-trivial bandgaps. In this study we investigate a oneway TOPOLOGICALly protected waveguide in the frequency range of f=6. 0 to 8. 0 GHz. The time reversal symmetry is broken by an applied MAGNETIC field in the z direction. We show that the waveguide propagates the light in only one direction that can be controlled by the applied MAGNETIC field and no backscattering is present in the waveguide which results in a near 100% transmission of light to the output. Furthermore, we investigate effect of the applied MAGNETIC field on the TOPOLOGICAL properties of the system by considering the material dispersion of the rods. Our results show that 3 different frequency ranges will be supported by the edge modes at each given MAGNETIC field. By increasing the magnitude of the applied MAGNETIC field, a blue shift in the non-trivial bandgap is seen, where it can be used to tailor the modes for the waveguide.

Optimization of electron scattering has been investigated using random potential barriers. Random pottential barriers can be defined in two ways: when these line defects are placed on the insulation surface, but strength of their potential is changing randomly, and the other is when potential barriers have a constant value, while their location on the surface of TOPOLOGICAL INSULATORS is changing randomly. To observe the better passage of electrons, the probability of transmission in the random potential state is calculated N times. These N values are averaged and with the probability of transmission, in the local potential state is compared. It seems that, to propagating of incident electron for some amount of incident energy, the number of defects, strength of potential and even direction of propagation electron, to the same result for the local line defects is close. But for some amounts of incident energy or some structural changes show significant changes.

In this paper, we have investigated the transport properties of the Dirac fermions on a TOPOLOGICAL insulator surface in the presence of external electric and MAGNETIC fields. For this reason, firstly we obtain the eigen energies (or eigenvalues) by using the Dirac Hamiltonian of the system for transmitted electrons via the surface and the Lorentz transformations. The conductance of the system is calculated by Landauer equation. Also, the effects of electric and MAGNETIC fields are investigated on the conductance and Fano factor effect. The application of the present results may be useful in designing devices based on molecular electronics in nanoscale.

In this study, Sendust (Fe85Si9. 6Al5. 4) nanostructure alloy was prepared by mechanical alloying and was characterized by X-ray diffraction. In addition, the alloy’ s morphology and its distribution particle size were investigated by scanning electron microscopy method. The alloyed powders were insulated with 4wt% of three different insulating materials including polyvinyl alcohol, epoxy resin, and sodium silicate. Then, 0. 5 wt% zinc stearate was added as a lubricant and the composites were formed at a pressure of 1600 MPa in a torodial die. These cores were annealed in Ar atmosphere at 350 to 450 º C for 1 h. Some of the MAGNETIC parameters of the as-milled and annealed samples were measured and compared with each other in the frequency range of 4 to 1000 kHz. The results showed that polyvinyl alcohol is not a suitable insulating agent for insulating this alloy. In addition, the real part of the initial MAGNETIC permeability of the MAGNETIC powder core insulated by sodium silicate in comparison with that insulated by epoxy resin is a bit smaller, but more reduction of the imaginary part of former results in an increase the Q-factor throughout measuring frequency range. The results show that annealing is more effective on improvement of the measured MAGNETIC properties of the samples insulated with sodium silicate than that insulated with epoxy resin.

The transport properties of the Dirac fermions through the electric and MAGNETIC barriers on the surface of a 3D TOPOLOGICAL insulator with a hexagonal warping effect have been investigated using the transfer matrix method. It was found that the transmission probability and the electric conductance are strongly modulated by the gate voltage, incident energy, number of barriers, and the exchange field strength. It was remarkable that the Dirac fermion is not perfectly transmitted at the normal incidence, confirming the role of the proximity effect in the suppression of transmission for normal incident electrons. The MAGNETIC field can open up a band gap in the conductance spectrum at the Dirac point, depending on the magnetization orientation. The time-reversal symmetry remains broken as long as the magnetization orientations in modulated regions are not entirely parallel to the surface of a TOPOLOGICAL insulator. The resonant states and the position of resonant peaks are dependent on the gate voltage and incident energy values. It is shown that the number of tunneling resonances increases with increasing the number of barriers. The hexagonal warping effect can increase electronic transport at high energies. The results found here are consistent with those obtained previously.

In this paper, we obtain a new class of $(n+1)$-dimensional MAGNETIC brane solutions of quasi-TOPOLOGICAL gravity in the presence of exponential and logarithmic nonlinear electrodynamics by a spinning MAGNETIC branes with one or more rotation parameters. For the spinning brane, the brane has a net electric charge, when one or more rotation are non zero, and also this electric charge is proportional to the magnitude of the rotation parameter. However, when all the rotation parameters are zero (static brane), the electric field vanishes and the brane has no net electric charge. In the class of solutions, we have a spacetime with an angular MAGNETIC field. These solutions are horizonless and have no curvature, but there is a conic singularity with a deficit angle. In addition, these two forms of nonlinear electrodynamics theory, have the same behaviors for the obtained solutions. Finally, we use the counterterm method and compute conserved quantities of these spacetimes.

In this paper we give some characterizations of TOPOLOGICAL extreme amenability. Also we answer a question raised by Ling [5]. In particular we prove that if T is a Borel subset of a locally compact semigroup S such that M(S)* has a multiplicative TOPOLOGICAL left invariant mean then T is TOPOLOGICAL left lumpy if and only if there is a multiplicative TOPOLOGICAL left invariant mean M on M(S)* such that M(XT)=1, where XT is the characteristic functional of T. Consequently if T is a TOPOLOGICAL left lumpy locally compact Borel subsemigroup of a locally compact semigroup S, then T is extremely TOPOLOGICAL left amenable if and only if S is.

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.

Background and Aims: Disc displacement is the most common temporomandibular joint disorder and MAGNETIC resonance imaging (MRI) is the gold standard in its diagnosis. This disorder can lead to changes in signal intensity of MAGNETIC resonance (MR). The purpose of this study was evaluation of correlation between relative signal intensity of MR images of retrodiscal tissue, superior and inferior head of lateral ptrygoid muscle with type of anterior disk displacement and condylar head flattening in patients with temporomandibular disorder (TMD).Materials and Methods: In this retrospective study, 31 MR images of patients who had anterior disc displacement were evaluated. After relative signal intensity measurement for retrodiscal tissue, superior and inferior head of lateral ptrygoid muscle, the correlation between relative signal intensity and type of anterior disc displacement was evaluated with repeated measure ANOVA test. In each of these 3 areas, t-test was used to compare the groups with and without condylar head flattening.Results: The correlation between relative signal intensity of MR images and type of anterior disc displacement in retrodiscal tissue, superior and inferior head of lateral ptrygoid muscle was not significant. There was also no statistically significant correlation between relative signal intensity of MR images and flattening of condylar head in retrodiscal tissue, superior and inferior head of lateral ptrygoid muscle (P>0.05).Conclusion: According to findings of this study, relative signal intensity of MR images in retrodiscal tissue, superior and inferior head of ptrygoid muscle is not a good predictor for type of anterior disc displacement and flattening of condylar head. It seems that this cannot be used as a diagnostic marker for TMD progression.