| 1. |
- Consolo, G., et al.
(author)
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Non-stationary excitation of two localized spin-wave modes in a nano-contact spin torque oscillator
- 2013
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In: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 114:15, s. 153906-
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Journal article (peer-reviewed)abstract
- We measure and simulate micromagnetically a framework based upon a nano-contact spin torque oscillator where two distinct localized evanescent spin-wave modes can be detected. The resulting frequency spectrum is composed by two peaks, corresponding to the excited modes, which lie below the ferromagnetic resonance frequency, and a low-frequency tail, which we attribute to the non-stationary switching between these modes. By using Fourier, wavelet, and Hilbert-Huang transforms, we investigate the properties of these modes in time and spatial domains, together with their spatial distribution. The existence of an additional localized mode (which was neither predicted by theory nor by previous numerical and experimental findings) has to be attributed to the large influence of the current-induced Oersted field strength which, in the present setup, is of the same order of magnitude as the external field. As a further consequence, the excited spin-waves, contrarily to what usually assumed, do not possess cylindrical symmetry: the Oersted field induces these modes to be excited at the two opposite sides of the region beneath the nano-contact.
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| 2. |
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| 3. |
- Dieny, B., et al.
(author)
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Opportunities and challenges for spintronics in the microelectronics industry
- 2020
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In: Nature Electronics. - : Springer Science and Business Media LLC. - 2520-1131. ; 3:8, s. 446-459
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Journal article (peer-reviewed)abstract
- This Review Article examines the potential of spintronics in four key areas of application -memories, sensors, microwave devices, and logic devices - and discusses the challenges that need be addressed in order to integrate spintronic materials and functionalities into mainstream microelectronic platforms. Spintronic devices exploit the spin, as well as the charge, of electrons and could bring new capabilities to the microelectronics industry. However, in order for spintronic devices to meet the ever-increasing demands of the industry, innovation in terms of materials, processes and circuits are required. Here, we review recent developments in spintronics that could soon have an impact on the microelectronics and information technology industry. We highlight and explore four key areas: magnetic memories, magnetic sensors, radio-frequency and microwave devices, and logic and non-Boolean devices. We also discuss the challenges-at both the device and the system level-that need be addressed in order to integrate spintronic materials and functionalities into mainstream microelectronic platforms.
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| 4. |
- Puliafito, V., et al.
(author)
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Hysteretic Synchronization in Spin-Torque Nanocontact Oscillators: A Micromagnetic Study
- 2014
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In: IEEE transactions on nanotechnology. - : Institute of Electrical and Electronics Engineers (IEEE). - 1536-125X .- 1941-0085. ; 13:3, s. 532-536
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Journal article (peer-reviewed)abstract
- Several experiments report the presence of finite jumps in the properties of spin-torque oscillators at room temperature, such as oscillation frequency and power as functions of current or field. On the basis of micromagnetic simulations, this paper links those experimental discontinuities to the changes in the curve slope numerically observed in the absence of thermal effects. Our numerical results show the key ingredient triggering this behavior is the presence of abrupt changes in the oscillation axis of the magnetization precession. We also predict that by fixing the bias point of the oscillator near those critical regions, it is possible to observe hysteretic synchronization. This result should be a key point in the design of nanoscale on-chip phase-locked loop receivers with improved sensitivity.
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| 5. |
- Puliafito, V., et al.
(author)
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Micromagnetic modeling of terahertz oscillations in an antiferromagnetic material driven by the spin Hall effect
- 2019
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In: Physical Review B. - 2469-9950. ; 99:2
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Journal article (peer-reviewed)abstract
- The realization of terahertz (THz) sources is a fundamental aspect for a wide range of applications. Over different approaches, compact THz oscillators can be realized, taking advantage of dynamics in antiferromagnetic thin films driven by the spin Hall effect. Here we perform a systematic study of these THz oscillators within a full micromagnetic solver based on the numerical solution of two coupled Landau-Lifshitz-Gilbert-Slonczewski equations, considering ultrathin films. We find two different dynamical modes depending on the strength of the Dzyaloshinskii-Moriya interaction (DMI). At low DMI, a large-amplitude precession is excited, where both the magnetizations of the sublattices are in a uniform state and rotate in the same direction. At large enough DMI, the ground state of the antiferromagnet becomes nonuniform and the antiferromagnetic dynamics is characterized by ultrafast domain-wall motion.
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