Spin-torque nano-oscillator based on two in-plane magnetized synthetic ferrimagnets

Abstract

We report the dynamic characterization of the spin-torque-driven in-plane precession modes of a spin-torque nano-oscillator based on two different synthetic ferrimagnets: a pinned one characterized by a strong RKKY interaction which is exchange coupled to an antiferromagnetic layer; and a second one, non-pinned characterized by weak RKKY coupling. The microwave properties associated with the steady-state precession of both SyFs are characterized by high spectral purity and power spectral density. However, frequency dispersion diagrams of the damped and spin transfer torque modes reveal drastically different dynamical behavior and microwave emission properties in both SyFs. In particular, the weak coupling between the magnetic layers of the non-pinned SyF raises discontinuous dispersion diagrams suggesting a strong influence of mode crossing. An interpretation of the different dynamical features observed in the damped and spin torque modes of both SyF systems was obtained by solving simultaneously, in a macrospin approach, a linearized version of the Landau-Lifshitz-Gilbert equation including the spin transfer torque term.

arXiv comment16 pages, 8 figures

References in corpus (19)

• Microwave Oscillations of a Nanomagnet Driven by a Spin-Polarized Current
• Direct-Current Induced Dynamics in Co90Fe10/Ni80Fe20 Point Contacts
• Spin torque building blocks
• Magnetic vortex oscillator driven by dc spin-polarized current
• Vowel recognition with four coupled spin-torque nano-oscillators
• Large microwave generation from d.c. driven magnetic vortex oscillators in magnetic tunnel junctions
• Ultralow-current-density and bias-field-free spin-transfer nano-oscillator
• Generation linewidth of an auto-oscillator with a nonlinear frequency shift: Spin-torque nano-oscillator
• Low-Energy Truly Random Number Generation with Superparamagnetic Tunnel Junctions for Unconventional Computing
• Mutual synchronization of spin torque nano-oscillators through a non-local and tunable electrical coupling
• Dynamics of two coupled vortices in a spin valve nanopillar excited by spin transfer torque
• Spin torque resonant vortex core expulsion for an efficient radio-frequency detection scheme
• Current-induced magnetization switching in MgO barrier magnetic tunnel junctions with CoFeB based synthetic ferrimagnetic free layers
• Quantized spin wave modes in magnetic tunnel junction nanopillars
• Auto-oscillation threshold and line narrowing in MgO-based spin-torque oscillators
• Ferromagnetic resonance study of composite Co/Ni - FeCoB free layers with perpendicular anisotropy
• Ferromagnetic resonance of exchange-coupled perpendicularly magnetized bilayers
• Spin torque driven dynamics of a coupled two layer structure: interplay between conservative and dissipative coupling
• Influence of interlayer coupling on the spin torque driven excitations in a spin torque oscillator