A5001740658- Magnetic properties of thin films
- Quantum and electron transport phenomena
- Advanced Memory and Neural Computing
- Ferroelectric and Negative Capacitance Devices
- Advanced Fiber Laser Technologies
- Mechanical and Optical Resonators
- Topological Materials and Phenomena
- Gyrotron and Vacuum Electronics Research
- Laser-Matter Interactions and Applications
- Additive Manufacturing and 3D Printing Technologies
- Cellular and Composite Structures
- Magnetic Properties and Applications
- Characterization and Applications of Magnetic Nanoparticles
- Semiconductor Quantum Structures and Devices
- Manufacturing Process and Optimization
- Photonic and Optical Devices
- Magneto-Optical Properties and Applications
- Scientific Research and Discoveries
- 2D Materials and Applications
- Advanced Research in Systems and Signal Processing
- Particle accelerators and beam dynamics
- Photorefractive and Nonlinear Optics
- Nonlinear Photonic Systems
- Politics and Conflicts in Afghanistan, Pakistan, and Middle East
- Energy Harvesting in Wireless Networks
National University of Singapore
2021-2024
Indian Institute of Technology Ropar
2024
Indian Institute of Technology Delhi
1979-2021
Arizona State University
2018-2019
University of Gothenburg
2016-2018
KTH Royal Institute of Technology
2016-2018
Argonne National Laboratory
2018
O. P. Jindal Global University
2017
University of Delhi
1995
Indian Institute of Technology Indore
1979
Abstract The mutual synchronization of spin-torque oscillators (STOs) is critical for communication, energy harvesting and neuromorphic applications. Short range magnetic coupling-based has spatial restrictions (few µm), whereas the long-range electrical using vortex STOs limited frequency responses in hundreds MHz (<500 MHz), restricting them on-chip GHz-range Here, we demonstrate four non-vortex uniformly-magnetized a single common current source both parallel series configurations at...
Spintronics has been recently extended to neuromorphic computing because of its energy efficiency and scalability. However, a biorealistic spintronic neuron with probabilistic "spiking" spontaneous reset functionality not demonstrated yet. Here, we propose device based on the heavy metal (HM)/ferromagnet (FM)/antiferromagnet (AFM) spin–orbit torque (SOT) heterostructure. The can autoreset itself after firing due exchange bias AFM. process is inherently stochastic competition between SOT AFM...
The β phase of Ta is known to exhibit higher spin Hall efficiency compared other heavy metals such as Pt. However, the larger resistivity β-phase leads power consumption for spin–orbit torque (SOT)-based devices. In this work, we measure damping-like and field-like in Ni80Fe20/Ta using spin-torque ferromagnetic resonance technique. We report a −(0.52 ± 0.01) with low-resistive mixed (α + β)-phase Ta, which about 40% Ta. found be lower (by ≈400%) opposite sign estimated mixed-phase system...
We demonstrate enhanced radio frequency (RF) detection sensitivity in a magnetic tunnel junction based spin torque oscillator (STO) using parametric synchronization. The synchronization is observed above the auto-oscillation threshold of STO and enhances RF at 2f0, where f0 frequency. maximum for 2f0≃9 GHz 16 mV/mW, while f0≃4.5 without 12 mV/mW. Macrospin simulations corroborate experimental results.
The frequency noise spectrum of a magnetic tunnel junction based spin torque oscillator is examined where multiple modes and mode-hopping events are observed. found to consist both white 1/f noise. We find systematic similar dependence on bias current the relative angle between reference free layers, which changes effective damping hence behavior in this system. at increases as layer aligned away from anti-parallel orientation w.r.t layer. These results indicate that origin related...
We study a wireless communication system based on magnetic tunnel junction spin-torque nano-oscillator (STNO) by employing amplitude-shift-keying modulation. By varying the pulse modulation frequency (f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> ) from 1 kHz to 2 MHz and distance (D) between antenna 25 150 cm, we show maximum data rate of 6 Mb/s (at D = cm f MHz), limit imposed our setup noise generated STNO itself. also report...
Abstract An important property of spin-torque nano-oscillators (STNOs) is their ability to produce a frequency modulated (FM) signal, which very critical for communication applications. We here demonstrate novel single sideband (SSB) modulation phenomenon using magnetic tunnel junction (MTJ)-based STNO, saves transmission bandwidth and in principle should minimize attenuation wireless communication. Experimentally, lower sidebands (LSSBs) have been successfully demonstrated over wide range...
A single term expression in the form of a Power law with two unknown coefficients is proposed. It explains fairly well energies ground bands even-even nuclei = 150-200 region. The index "b" and coefficient "a" this are constant independent level spin, below back bending energy. Variation average Z N, valence nucleon pair product Np Nn also illustrated agrees general expectations.
We report on a time-domain study of parametric synchronization in magnetic tunnel junction based spin torque nano-oscillator (STNO). Time-domain measurements the instantaneous frequency ($f_{i}$) parametrically synchronized STNO show random short-term unlocking signal for low injected radio-frequency (RF) power, which cannot be revealed time-averaged domain measurements. Macrospin simulations reproduce experimental results and reveal that during is driven by thermal fluctuations. using high...
Integration of active elements into silicon wafers is the first step towards their usage in modern electronic devices based on nanometric structures. Spintronic terahertz emitters, typically composed nanometer-thin magnetic multilayer, have outstanding capability producing high-quality, broadband pulses using extremely simple heterostructures. A question remains whether an efficient and cheap integration with other silicon-based technologies can be achieved. We show here that simply having a...
We studied the bias dependence of spin transfer torque in MgO-based magnetic tunnel junction using a field-modulated ferromagnetic resonance measurement technique for three devices with tunneling magnetoresistances (MRs) 60%, 67%, and 73%, respectively. The lower MR ratio showed presence multiple modes, while device higher (73%) single mode. found out-of-plane torkance our compared to in-plane torkance. is linear applied bias, shows strong on hence barrier quality.
The phenomenon of nonlinear propagation and self-distortion an amplitude-modulated microwave in a plasma-filled rectangular waveguide was investigated. microwave, on account its nonuniform intensity distribution the transverse direction, gives rise to ponderomotive force electrons causes redistribution plasma density. Consequently, constant becomes function wave is modulated accordance with amplitude envelope wave. This results severe distortion A typical beam omega approximately=1010 rad...
The modulation bandwidth ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${f}_{{BW}}$ </tex-math></inline-formula> ) is a critical figure-of-merit for wireless communication applications of spin torque nano-oscillators (STNOs) as it determines the maximum data rate. Although both theory and previous experiments have shown that in STNOs governed by amplitude relaxation frequency...
Wireless transmission requires a circuitry to generate GHz range signal. Spin transfer torque devices are one of the promising candidates for generating stable signal in through collective precession local spins ferromagnetic layer, known as free layer. Another fixed acts medium convert incoming electric current into spin polarized current. This drives layer constant precession. Factors like high linewidth, low output power and modulation rate yet be optimized make these ready use practical...
Recent interest in quantum nonlinearity has spurred the development of rectifiers for harvesting energy from ambient radiofrequency waves. However, these face efficiency and bandwidth limitations at room temperature. We address challenges by exploring Bi
A high-power microwave propagating through a plasma-filled waveguide gives rise to the generation of second and third harmonic waves because ponderomotive force energy-dependent collisions, respectively. The generated harmonics possess very different kind intensity distribution than that normal modes. efficiency is resonantly enhanced at some optimum size such 2β1=β2, i.e., n2π2/b2+(m2−4) π2/a2= 3ωp2/c2 where β1 β2 are propagation constants fundamental This effect might account for observed...
The phenomenon of nonlinear mixing two microwave beams nearly the same frequency ( omega 1, 2) and generation 1+or- 2 waves has been studied in a rectangular waveguide. nonlinearity arises through ponderomotive force on electrons. It is seen that yield difference much larger than sum generation. This suggests submillimetre may be efficiently generated by laser beams.
We report on a macrospin simulation study of field angle dependent single sideband (SSB) generation in spin-torque nano- oscillator with free layer magnetized the film plane. show that during analog modulation spin torque nano-oscillator depends strongly in-plane angle. validate our results by using non-linear frequency and amplitude theory which describes angular dependence taking into account nonlinear sensitivity coefficients. propose an optimum range for SSB generation.