Berlin 2018 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 21: Poster I
MA 21.98: Poster
Dienstag, 13. März 2018, 09:30–13:00, Poster A
Low frequency noise in TMR based vortex spin torque nano-oscillators — •Steffen Wittrock1, Kay Yakushiji2, Akio Fukushima2, Hitoshi Kubota2, Shinji Yuasa2, Paolo Bortolotti1, Enrico Rubiola3, and Vincent Cros1 — 1Unité Mixte de Physique CNRS/Thales, Univ. Paris-Sud, 91767 Palaiseau, France — 2National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki 305-8568, Japan — 3Time-Frequency department, CNRS FEMTO-ST, Université de Franche Comté, 25030 Besançon, France
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. The key property of spin-torque nano-oscillators (STNOs) is their high nonlinearity which gives rise to manifold phenomena as well as to their relatively poor spectral coherence and coupled noise behavior. While the noise distribution for offset frequencies far from the carrier frequency is reasonably well understood and described by the general nonlinear autooscillator theory, low frequency noise remains under investigation as it limits the frequency stability of the oscillator. Extensively studied in GMR and TMR sensors, this work addresses the low frequency noise of a TMR-based spin-torque vortex oscillator. We investigate the noise dependence on the active magnetic volume of the oscillation under various field and current conditions as well as its link to nonlinearity.