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In the present work, we have modeled a heterogeneous Magneto Resistance Tilted Polarizer-based Spin Torque Nano Oscillator [MRTP-STNO] theoretically. The idea of the work is to investigate the impact of thermal noise on the frequency as well the PSD of the above mentioned device by including the Hth in the Heff. The precession of magnetization dynamics led by Spin Transfer Torque [STT] is studied numerically by solving the equation called Landau-Lifshitz-Gilbert-Slonczewski [LLGS]. Here, β is the independent tilt angle of the fixed layer and θ is the angle between free layer magnetization and the easy axis of the device, respectively. Both the angles can be varied from 10° to 90° as an increment of 10°. The maximum frequency of the modeled device is about 235.5 GHz and PSD of 1.74 µW/mA2/GHz in the absence of thermal noise and in the presence of thermal noise the frequency as well as the corresponding PSD is recorded as 215.4 GHz and PSD of 1.70 µW/mA2/GHz. The author sparks that the modeled device applies to High-Frequency applications and opens a new platform for forthcoming devices during its practical usage. [ABSTRACT FROM AUTHOR]

In this study, we have modeled a simple Spin Torque Nano Oscillator [STNO] of Tri and Penta layer structure theoretically, using macro-spin approach. Tri-layer Spin Torque Nano Oscillator [T-STNO], refers to a device made up of three layers comprising of a couple of Ferro-Magnetic layers separated between a Non-Magnetic [NM] spacer (i.e.) [FM1/NM1/FM2]. Penta-layer Spin Torque Nano Oscillator [P-STNO] refers that the device is made up of five layers which comprised of three FM layers aligned between two NM spacer (i.e.) [FM1/NM1/FM2/NM2/FM3]. The idea of the work is to investigate and report the results of the P-STNO, (which grabbed many researchers' attention) and to compare its functionalities with the conventional T-STNO which has been commercialized, already. The magnetization precession dynamics led by Spin Transfer Torque [STT] is studied numerically by solving the equation called Landau-Lifshitz-Gilbert-Slonczewski [LLGS]. The author wishes that the designed P-STNO device open a new window for the spintronic based devices because of its superior output functionalities as compared to the conventional T-STNO device. [ABSTRACT FROM AUTHOR]

Here, tShe authors have designed a heterogeneous Current Induced Oersted Field based Magneto Resistance Tilted Polarizer-Spin Torque Nano Oscillator [CIOF-MRTP-STNO] in a theoretical manner. The idea of the work is to investigate the impact of thermal noise on the frequency as well the PSD of the above modelled device by including the Hth in the Heff by macro-magnetic approach. The magnetization precession dynamics guided by Spin Transfer Torque [STT] is studied numerically by solving the governing equation called Landau-Lifshitz-Gilbert-Slonczewski [LLGS]. Here, β is the independent tilt angle of the fixed layer and θ is the angle between free layer magnetization and the easy axis of the device, respectively. In the device, both the angles β and θ can be varied from 10° to 90° as an accretion of 10°. The maximum frequency of the modeled device is about 197 GHz and PSD of 1.67 µW/mA2/GHz in the presence of thermal noise with Hoe = 50 kA/m (in the presence of CIOF), but in the absence of thermal noise, the frequency and the PSD emitted by the device is reduced to 180 GHz and 1.63 µW/mA2/GHz. On the other hand, in the presence of thermal noise with Hoe=0 kA/m (in the absence of CIOF), the device emits the frequency and PSD of 137 GHz and 1.51 µW/mA2/GHz, but in the absence of thermal noise, the frequency and the PSD emitted by the device is reduced to 125 GHz and 1.48 µW/mA2/GHz. The author suggests that the modeled device is applicable to High-Frequency applications. [ABSTRACT FROM AUTHOR]

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]

In the present study, we have theoretically modeled a heterogeneous Tilted Polarizer [TP] based Spin Torque Nano Oscillator [STNO] with two independent variables (β & θ). The magnetization precession dynamics led by Spin Transfer Torque [STT] is numerically studied by solving the Landau-Lifshitz-Gilbert-Slonczewski [LLGS] equation. Here, β & θ are the TP angle and the angle between free layer magnetization and the easy axis of the device respectively. Both β & θ can be varied from 0° to 90°. For every particular β, we varied the θ from 10° to 90°. It is ostensibly visible that in all the tilt angles, the frequency is accessible and highly tunable in the order of GHz. The maximum frequency of the device is obtained at β = 60° & θ = 90°. The obtained frequency is 227 GHz and PSD of 1.719 µW/mA2/GHz with a solid current density of 8 × 1010 A/m2 with a zero applied field. To the best of the author's knowledge, we have reported the maximum frequency emitted by a single STNO of about 227 GHz, which is highly applicable for Extremely-High-Frequency applications. It opens a new door for the clutter breaking innovations in the field of spin based electronics. [ABSTRACT FROM AUTHOR]

The current induced magnetization precession dynamics by Spin Transfer Torque [STT] in a Spin Torque Nano Oscillator [STNO] device is investigated numerically by solving the Landau Lifshitz Gilbert Slonczewski [LLGS] equation. In the present study, we have devised a Heterogeneous based STNO device made of Ferro Magnetic [FM] Alloy. The base layer is made of Fe85B13Ni2 and the apex layer is made of Co2Fe0.4Mn0.6Si. The copper acts as a Non-Magnetic [NM] spacer. We have introduced the Current Induced Oersted Field [CIOF] and it is generated when the spin polarized current passes through the device. By varying the generated Oersted Field [OF] strength (Hoe) from 0 kA/m to 50 kA/m, as an increment of 10 kA/m the frequency tunability is achieved. The result imputes that, if we increase the OF strength from 0 kA/m to 50 kA/m frequency keeps on increasing, but the Power reduces. At 0 kA/m (in the absence of the OF), 26.36 GHz frequency with 6.116 (nW/mA2/GHz) is obtained. On the other hand, at 50 kA/m (in the presence of the OF), 115.9 GHz frequency with 2.105 (nW/mA2/GHz) is obtained. The author insinuates that the results are applicable for nanoscale spintronic devices in Extremely High-Frequency applications. [ABSTRACT FROM AUTHOR]

In the present work, we have reported the results based on the effect of Bi-Quadratic Coupling [BQC] as well as the Orange Peel Coupling [OPC] in different Heterogeneous based Spin Torque Nano Oscillator [STNO] device. STNO, comprised of trilayer (X/Cu/Py) (i.e) two ferromagnetic layers separated by a non magnetic spacer. Those Ferro Magnetic [FM] layers are called fixed and free, because the corresponding magnetization tends to be fixed and free. Throughout the macro magnetic framework, Cu is taken as the non magnetic spacer and Py is taken in free layer. X (= Fe and Co) denotes the FM taken in the pinned layer for both the BQC and OPC coupling mechanism. The magnetization switching dynamics of the free layer for all devices are studied by solving the governing Landau-Lifshitz-Gilbert-Slonczewski [LLGS] equation. For all the four devices, switching time is calculated in the presence and absence of both BQC and OPC separately. The switching time for BQC based device [Co/Cu/Py] is calculated as 136 ps and 166 ps in the presence and absence respectively. Similar results are found in another BQC based device [Fe/Cu/Py]. The calculated switching time for the device is 135 ps and 181 ps in the presence and absence respectively. As far as the OPC is concerned, the switching time for the device [Co/Cu/Py] is found to be 111 ps and 160 ps in the presence and absence respectively. Relatively, other OPC based device [Fe/Cu/Py] switches 113 ps and 163 ps in the presence and absence respectively. The results depicts that OPC based devices switches rapidly as compared to BQC based devices which are highly applicable in ultra high density recording media. [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]

In this micromagnetic framework, Spin transfer torque induced magnetization switching in Co/Cu/Co nanopillar device is investigated numerically. The magnetization switching dynamics of the free layer in the nanopillar device is governed by the Landau Lifshitz Gilbert Slonczewski (LLGS) equation and solving it numerically by employing OOMMF, a micromagnetic software. Results are obtained by varying the fixed layer orientation (β) of our nanopillar device from in-plane to out-of-plane (i.e.) from 0° to 80° and the corresponding switching time is noted. Results of the micromagnetic simulation reveals that there is an extreme reduction of switching time in the free layer of our devised nanopillar, if we increase the fixed layer angle (β) from 0° to 80°. The corresponding switching time got shortened from 1651 picoseconds to 104.44 picoseconds and is obtained for an applied current density of 2.25×1011Am-2 with 0.05 T as applied bias field. For 90° (i.e.) out-of-plane orientation, the magnetization switching is not exist, because the free layer magnetization follows an oscillation state. Moreover, when we compare 0° to 80°, the switching time is reduced almost 16 times which solely provoked as a source of future spintronic devices for magnetic storage applications. [ABSTRACT FROM AUTHOR]