scholarly journals High-frequency spin wave modes excited by strain pulse in vortex state magnetostrictive nanomagnets

AIP Advances ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 125314
Author(s):  
Huanqing Cui ◽  
Xiaokuo Yang ◽  
Lin Ni ◽  
Mingliang Zhang ◽  
Jiahao Liu ◽  
...  
Keyword(s):  
Spin Wave ◽  
High Frequency ◽  
Vortex State ◽  
Strain Pulse ◽  
Wave Modes

scholarly journals Engineered Magnetization Dynamics of Magnonic Nanograting Filters

2021 ◽  
Vol 7 (6) ◽  
pp. 81
Author(s):  
Rawana Yagan ◽  
Ferhat Katmis ◽  
Mehmet C. Onbaşlı
Keyword(s):  
Spin Wave ◽  
High Frequency ◽  
Excitation Frequency ◽  
Frequency Multiplier ◽  
Magnetic Nanowires ◽  
Frequency Multipliers ◽  
Low Loss ◽  
Magnonic Crystals ◽  
Wave Filters ◽  
Wave Modes

Magnonic crystals and gratings could enable tunable spin-wave filters, logic, and frequency multiplier devices. Using micromagnetic models, we investigate the effect of nanowire damping, excitation frequency and geometry on the spin wave modes, spatial and temporal transmission profiles for a finite patterned nanograting under external direct current (DC) and radio frequency (RF) magnetic fields. Studying the effect of Gilbert damping constant on the temporal and spectral responses shows that low-damping leads to longer mode propagation lengths due to low-loss and high-frequency excitations are also transmitted with high intensity. When the nanowire is excited with stronger external RF fields, higher frequency spin wave modes are transmitted with higher intensities. Changing the nanowire grating width, pitch and its number of periods helps shift the transmitted frequencies over super high-frequency (SHF) range, spans S, C, X, Ku, and K bands (3–30 GHz). Our design could enable spin-wave frequency multipliers, selective filtering, excitation, and suppression in magnetic nanowires.

Soliton-Magnon Scattering and Spin Wave Modes for a Small Magnetic Particle in the Vortex State

2001 ◽  
Vol 373-376 ◽  
pp. 803-806 ◽  
Author(s):  
D.D. Sheka ◽  
V.M. Murav'yov ◽  
I.A. Yastremsky ◽  
B.A. Ivanov
Keyword(s):  
Spin Wave ◽  
Magnetic Particle ◽  
Vortex State ◽  
Wave Modes

scholarly journals Electrical characterisation of higher order spin wave modes in vortex-based magnetic tunnel junctions

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Alex. S. Jenkins ◽  
Lara San Emeterio Alvarez ◽  
Samh Memshawy ◽  
Paolo Bortolotti ◽  
Vincent Cros ◽  
...  
Keyword(s):  
Spin Wave ◽  
Tunnel Junctions ◽  
Magnetic Tunnel Junctions ◽  
Higher Order ◽  
Spin Torque ◽  
Micromagnetic Simulations ◽  
Higher Order Modes ◽  
Spin Diode ◽  
Super High Frequency ◽  
Wave Modes

AbstractNiFe-based vortex spin-torque nano-oscillators (STNO) have been shown to be rich dynamic systems which can operate as efficient frequency generators and detectors, but with a limitation in frequency determined by the gyrotropic frequency, typically sub-GHz. In this report, we present a detailed analysis of the nature of the higher order spin wave modes which exist in the Super High Frequency range (3–30 GHz). This is achieved via micromagnetic simulations and electrical characterisation in magnetic tunnel junctions, both directly via the spin-diode effect and indirectly via the measurement of the coupling with the gyrotropic critical current. The excitation mechanism and spatial profile of the modes are shown to have a complex dependence on the vortex core position. Additionally, the inter-mode coupling between the fundamental gyrotropic mode and the higher order modes is shown to reduce or enhance the effective damping depending upon the sense of propagation of the confined spin wave.

scholarly journals Phase resolved observation of spin wave modes in antidot lattices

2021 ◽  
Vol 118 (23) ◽  
pp. 232403
Author(s):  
Felix Groß ◽  
Mateusz Zelent ◽  
Ajay Gangwar ◽  
Sławomir Mamica ◽  
Paweł Gruszecki ◽  
...  
Keyword(s):  
Spin Wave ◽  
Wave Modes

Intensity distribution, evolution, and dispersion of discrete spin wave modes in nanoscale spin-torque oscillator

2021 ◽  
Vol 129 (24) ◽  
pp. 243903
Author(s):  
Shizhu Qiao ◽  
Lihui Bai ◽  
Haibin Xue ◽  
Lipeng Hou ◽  
Lijuan Zhang ◽  
...  
Keyword(s):  
Spin Wave ◽  
Intensity Distribution ◽  
Spin Torque ◽  
Wave Modes

scholarly journals Size-dependent magnetization switching characteristics and spin wave modes of FePt nanostructures

2013 ◽  
Vol 113 (20) ◽  
pp. 203910 ◽  
Author(s):  
R. Brandt ◽  
R. Rückriem ◽  
D. A. Gilbert ◽  
F. Ganss ◽  
T. Senn ◽  
...  
Keyword(s):  
Spin Wave ◽  
Magnetization Switching ◽  
Size Dependent ◽  
Switching Characteristics ◽  
Wave Modes

Thermally excited spin wave modes in synthetic antiferromagnetic stripes

2007 ◽  
Vol 310 (2) ◽  
pp. 1949-1951 ◽  
Author(s):  
Yasuo Ando ◽  
Young Min Lee ◽  
Tatsuya Aoki ◽  
Terunobu Miyazaki ◽  
Helmut Schultheiß ◽  
...  
Keyword(s):  
Spin Wave ◽  
Wave Modes

scholarly journals High Frequency Ultrasonic Wave Propagation in  Anisotropic Materials

2021 ◽  
Author(s):  
◽  
Andrew Paul Dawson
Keyword(s):  
Wave Propagation ◽  
Ultrasonic Wave ◽  
High Frequency ◽  
Guided Wave ◽  
Ultrasonic Waves ◽  
Tissue Characterisation ◽  
Ultrasonic Wave Propagation ◽  
Matching Layer ◽  
Fibrous Tissues ◽  
Wave Modes

<p>The influence of highly regular, anisotropic, microstructured materials on high frequency ultrasonic wave propagation was investigated in this work. Microstructure, often only treated as a source of scattering, significantly influences high frequency ultrasonic waves, resulting in unexpected guided wave modes. Tissues, such as skin or muscle, are treated as homogeneous by current medical ultrasound systems, but actually consist of highly anisotropic micron-sized fibres. As these systems increase towards 100 MHz, these fibres will significantly influence propagating waves leading to guided wave modes. The effect of these modes on image quality must be considered. However, before studies can be undertaken on fibrous tissues, wave propagation in more ideal structures must be first understood. After the construction of a suitable high frequency ultrasound experimental system, finite element modelling and experimental characterisation of high frequency (20-200 MHz) ultrasonic waves in ideal, collinear, nanostructured alumina was carried out. These results revealed interesting waveguiding phenomena, and also identified the potential and significant advantages of using a microstructured material as an alternative acoustic matching layer in ultrasonic transducer design. Tailorable acoustic impedances were achieved from 4-17 MRayl, covering the impedance range of 7-12 MRayl most commonly required by transducer matching layers. Attenuation coefficients as low as 3.5 dBmm-1 were measured at 100 MHz, which is excellent when compared with 500 dBmm-1 that was measured for a state of the art loaded epoxy matching layer at the same frequency. Reception of ultrasound without the restriction of critical angles was also achieved, and no dispersion was observed in these structures (unlike current matching layers) until at least 200 MHz. In addition, to make a significant step forward towards high frequency tissue characterisation, novel microstructured poly(vinyl alcohol) tissue-mimicking phantoms were also developed. These phantoms possessed acoustic and microstructural properties representative of fibrous tissues, much more realistic than currently used homogeneous phantoms. The attenuation coefficient measured along the direction of PVA alignment in an example phantom was 8 dBmm-1 at 30 MHz, in excellent agreement with healthy human myocardium. This method will allow the fabrication of more realistic and repeatable phantoms for future high frequency tissue characterisation studies.</p>

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