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Dipole-exchange spin waves (SWs) propagation in the air gap and bicomponent magnonic waveguides (BMWs) encompassed with alternating $SM$ and $N$ stripes based on different saturation magnetization ($M_{s}$) is studied through micromagnetic simulation. The air gaps MWs (AMWs) exhibit the transmission bands in the range ≈3–10 GHz as a result of inhomogeneous demagnetization field around the $N$ stripes (air gaps), where the magnetostatic coupling helps to propagate the SWs in entire waveguides with low group velocity $v_{g} \approx 28$ –380 m/s. By incorporating two different $M_{s}$ , magnetic materials in both $SM$ and $N$ stripes form BMWs enhancing the transmission bands from narrow to the wide range which is ≈14–60 GHz due to large exchange coupling at the interfaces. It increases the intercoupling between neighboring stripes, which reduces the energy loss of SWs that can be propagated throughout the entire waveguide with large group velocity $v_{g} \approx 8500$ –10600 m/s. The design of AMWs and BMWs would be suitable to construct an efficient signal processing device with high group velocity and wide transmission bands depending on periodicity and saturation magnetization present in the MWs. [ABSTRACT FROM AUTHOR]

Dipole-exchange spin waves (SWs) propagating in a 1-D magnonic waveguide embedded with different orientations of triangular antidots are investigated through the micromagnetic simulation. The dipole-exchange SW propagation is affected due to the effect of changing the triangular antidots orientation. This leads to reduction in the number of forbidden bands and their gap width in the magnonic waveguide. The SW characteristics are interpreted by plotting frequency dispersion curves and analyzing the power and phase distribution profile (PPDP) and static demagnetization field profile to substantiate the occurrence of bandgaps. The number of forbidden bands and their gap width get reduced due to the formation of symmetric and antisymmetric modes, and it will be further clarified by the PPDPs. For θ = 0°, four wide bandgaps are recorded; I and II bandgaps are due to symmetric modes, whereas the remaining gaps are due to antisymmetric modes. From θ = 0° to 90°, the number of forbidden bands is reduced from 4 to 2 because of the inhomogeneous distribution of the internal field introduced by the presence of triangular array antidots in the transverse direction, and it is confined via the static demagnetization field. The way to develop magnonic antidot-based waveguide for SW filter applications is paved by opening, closing, and tuning of the gap width. This can be effectively brought about by changing the orientation of triangular antidots. [ABSTRACT FROM AUTHOR]

In this paper, we theoretically devised a spin torque nano-oscillator (STNO) with tilted polarizer (TP) with the help of two independent variables ( \beta and \theta ). The spin torque induced magnetization precession dynamics is studied numerically by solving the governing Landau–Lifshitz–Gilbert–Slonczewski equation. The TP STNO free layer precession frequency is determined by varying TP angle ( \beta ) from 0° to 90°. For a particular value of \beta , we can vary ( \theta /GHz/mA2 is obtained for \beta =60 ^\circ and \theta =90 ^\circ with the applied current density of 10\times 10^10 Am−2. Moreover, our results allow great freedom in choosing the detailed layer structure of the TP STNO and these findings pave a new route for the implementation of nanoscale microwave sources for future generation integrated electronics. [ABSTRACT FROM AUTHOR]

Nonlinear localized magnetic excitations in 1-D bicomponent magnonic crystal are investigated under periodic magnetic field of spatially varying strength with spin current. The governing modified Landau–Lifshitz equation with spin current is transformed into the variable coefficient nonlinear Schrödinger (VCNLS) equation using a stereographic projection. In general, the VCNLS equation is nonintegrable and by using similarity transformation technique, the VCNLS equation is reduced into the standard NLS equation with certain integrability conditions. A systematic connection between the solution of VCNLS and NLS equations is established. The solution of VCNLS equation is obtained using the solution of the NLS equation. The excitation of magnetization is in the form of solitons on the oscillatory background with structure similar to the form of spin Bloch waves, and in addition, the spin current controls the soliton velocity. The velocity of soliton is directly proportional to the strength of current density and inversely proportional to the average saturation magnetization value, which is the value of saturation magnetization of the composite material at the interface of the two ferromagnetic materials, which are used to form the bicomponent magnonic crystal. [ABSTRACT FROM AUTHOR]