Low frequency noise in vortex spin torque nano-oscillators
| Autor: | Wittrock, Steffen, Yakushiji, Kay, Fukushima, Akio, Kubota, Hitoshi, Bortolotti, Paolo, Ebels, Ursula, Yuasa, Shinji, Cibiel, Gilles, Galliou, Serge, Rubiola, Enrico |
|---|---|
| Přispěvatelé: | Université Paris-Sud - Paris 11 (UP11), Spintronics Research Center, National Institute of Advanced Industrial Science and Technology (AIST), THALES, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre National d'Études Spatiales [Toulouse] (CNES), Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), THALES [France], Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC) |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | International Magnetic Conference International Magnetic Conference, Jul 2018, Singapore, Singapore |
| Popis: | International audience; With their very rich static and dynamical properties, magnetic vortex dynamics excited by a spin polarized current represent not only a model system to study the physical mechanisms of spin transfer phenomena but could also give birth to a new generation of multi-functional microwave spintronic devices [1]. The key property of spin-torque nano-oscillators (STNOs) is their high nonlinearity [2] which gives rise to manifold phenomena such as injection locking to an external rf signal [3], [4] or synchronization of multiple STNOs [5]-[7]. On the other hand, their large nonlinearity causes the oscillator's very poor spectral coherence and leads to a coupling between amplitude and phase noise [8]. While the noise distribution for offset frequencies far from the carrier frequency is reasonably well understood [8] and described by the general nonlinear autooscillator theory [2], low frequency noise remains under investigation as it limits the frequency stability of the oscillator. Extensively studied in GMR and TMR sensors [9]-[12], this work addresses the low frequency noise of a TMR-based spin-torque vortex oscillator in the regime of large amplitude steady oscillations. In detail, we present a precise experimental study of the TMR-based spin-torque vortex oscillator's low frequency noise, which remains poorly investigated for STNOs in the regime of large amplitude steady oscillations, as we propose here. The measured STNO's magnetic tunnel junction layer stack of PtMn/CoFe/Ru/ CoFeB/CoFe/MgO/FeB/MgO/Ta/Ru was realized by sputter deposition and nanopillar devices of 100-600nm were nanofabricated. The devices have a free running frequency from 100 MHz to 1 GHz depending on the diameter and the applied field value, with an integrated power of up to a few μW and a linewidth of typically ~100 kHz. In complement to the experimental measurements, we have also developed a phenomenological theory aiming to investigate the low frequency flicker noise in these vortex-STNOs. Starti... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|