Auto-oscillation threshold and line narrowing in MgO-based spin-torque oscillators

Abstract

We present an experimental study of the power spectrum of current-driven magnetization oscillations in MgO tunnel junctions under low bias. We find the existence of narrow spectral lines, down to 8 MHz in width at a frequency of 10.7 GHz, for small applied fields with clear evidence of an auto-oscillation threshold. Micromagnetics simulations indicate that the excited mode corresponds to an edge mode of the synthetic antiferromagnet.

References in corpus (6)

• Microwave Oscillations of a Nanomagnet Driven by a Spin-Polarized Current
• Direct-Current Induced Dynamics in Co90Fe10/Ni80Fe20 Point Contacts
• Bias-driven large power microwave emission from MgO-based tunnel magnetoresistance devices
• Generation linewidth of an auto-oscillator with a nonlinear frequency shift: Spin-torque nano-oscillator
• Current-driven microwave oscillations in current perpendicular-to-plane spin-valve nanopillars
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Cited by in corpus (6)

• Quantized spin wave modes in magnetic tunnel junction nanopillars
• Bias dependence of perpendicular spin torque and of free and fixed layer eigenmodes in MgO-based nanopillars
• Direct experimental measurement of phase-amplitude coupling in spin torque oscillators
• Coherent microwave generation by spintronic feedback oscillator
• Effects of delayed feedback on the power spectrum of spin-torque nano-oscillators
• Spin-torque nano-oscillator based on two in-plane magnetized synthetic ferrimagnets