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Spin wave propagation in air-gap stripes and bicomponent magnonic waveguides are studied through the micromagnetic simulation. The magnonic waveguides composed of M and N stripes based on different values of saturation magnetization. In air-gap stripes magnonic waveguides, the air-gaps in N (i.e., Ms = 0) are sandwiched between the M of magnetic materials where the magnetostatic coupling take place due to the inhomogeneous field. In bicomponent magnonic waveguides(BMW), the exchange interaction is dominant due to the presence of two magnetic materials (M and N stripes). The exchange interaction plays a major role in BMW existing at the interfaces of different magnetic materials which enhance the SWs propagation. Air - gap stripes based magnonic waveguides exhibit the transmission bands in range of ≈ 3-5 GHz and bicomponent exhibits ≈ 14-39 GHz, respectively. This work paves the way to develop the narrow and wide transmission bands based on magnonic waveguide which is suitable for signal transmission and processing devices. [ABSTRACT FROM AUTHOR]

The present work deals with the theoretical modeling of Spin Hall Spin Torque Nano Oscillator (SHSTNO) using four different Ferromagnetic Materials (FM) (Py, Co, CoFeB and Ni) with Current In Plane (CIP) geometry. The device comprised of bilayer (Pt/X) (i.e.)a top Ferromagnetic Free Layer (FFL) which is notated as (X) along with the heavy metal (Pt). In this work, we tried to tune the frequency of the device by using different materials in FFLand by altering the Spin Hall Angle (SHA), which is notated as (θ). The sustained oscillation in the FFL is studied by the governing LandauLifshitz-Gilbert-Slonczewski (LLGS) equation. The device works under the principle called Spin Hall Effect (SHE) that originates from spin-orbit scattering paves for the deflection of conduction electrons with opposite signs oriented in the opposite direction. When the spin reaches FFL due to the phenomena called Spin Transfer Torque (STT), persistent oscillation occurs, resulting in the emission of frequency in the microwave regime. The SHA (θ) is highly tunable up to 0.8 from 0.1. The author mentions that one can vary (θ) to the maximum and use the low Saturation Magnetization (SM) based material in FFL for maximum frequency tunability. The results presented in the article can find the application as spinwave emitters for magnonic applications where the spin waves may use for transmission and processing information. [ABSTRACT FROM AUTHOR]

We theoretically modelled a couple of Spin Hall Spin Torque Nano Oscillator [SHSTNO] with Current In Plane [CIP] Geometry. In general, the device comprised of bilayer (i.e.) a Ferro magnetic free layer [Co and CoFeB] along with the heavy metal [Pt]. The main motto of the present study is to tune the frequency of the above mentioned devices by altering the Spin Hall Angle [SHA] (θ). The sustained oscillation in the oscillating free layer is studied by the governing Landau-Lifshitz-Gilbert- Slonczewski [LLGS] equation. The devices mainly works under the principle of Spin Hall Effect [SHE], which originates from spin orbit scattering paves for the deflection of conduction electrons with opposite signs oriented in opposite direction. When the spin reaches the free layer due to the Spin Transfer Torque phenomena [STT], persistent oscillation occurs which end up in emitting the microwave frequency. Those are highly tunable with the aid of (θ), which generally varies from 0.1 to 0.9. The author sparks that for maximum frequency tunability, one can easily vary the SHA, (θ) to the maximum with the free layer of minimal thickness paves for the maximum frequency emission by the device. For CoFeB device, at free layer thickness of about 3 nm and the corresponding SHA of about 0.8, the maximum frequency of 67.8 GHz is obtained. The author emphasize that, the results shown here can find the application as spin wave emitters for magnonic applications where the spin waves are used for transmission and processing information on nano scale level. [ABSTRACT FROM AUTHOR]

Spin waves in ID periodic triangular array of antidots are encarved in a permalloy magnonic waveguide is investigated through micromagnetic simulation. The effect of the rotating array of antidots and in-plane rotation of the scattering centers on the band structure are investigated, to indicate new possibilities of fine tuning of spin-wave filter pass and stop bands. The results show that, the opening and closing of band gaps paves a way for band pass and stop filters on waveguide. From the results, the scattering center and strong spatial distribution field plays crucible role for controlling opening and closing bandgap width of ∼12 GHz for 0° rotation. We have obtained a single narrow bandgap of width 1GHz is obtained for 90° rotation of the antidot. Similarly, the tunability is achieved for desired microwave applications done by rotating triangular antidots with different orientation. [ABSTRACT FROM AUTHOR]

Spin wave (SW) propagation in 1-D magnonic antidot waveguides (MAWs) having different width w modulation of square shaped antidots studied through the micromagnetic simulation. The varying width modulation on square antidots affects the spin wave propagation in the waveguide. The inhomogeneity of the demagnetization field will increases when the width w of antidots increases, due to the Bragg's reflection of SW takes place along the width direction. Hence, the wider width of the second bandgap can be achieved, such as (II: 7.09 GHz) and (II: 19.29 GHz) for [12 12] and [12 18]. The achieved two bandgaps (I) and (II) are direct ones, and their origins can be understood through the spatial distribution profiles of power and phase (PPDPs) in the waveguides. This work paves the way to develop efficient SW filters based on MAWs at the nanoscale, which is highly useful in microwave communications. [ABSTRACT FROM AUTHOR]