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arXiv · 1811.00106

Zero-field dynamics stabilized by in-plane shape anisotropy in MgO-based spin-torque oscillators

Ewa Kowalska·Attila Kákay·Ciarán Fowley·Volker Sluka·Jürgen Lindner·Jürgen Fassbender·Alina M. Deac
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Abstract

Here we demonstrate numerically that shape anisotropy in MgO-based spin-torque nano-oscillators consisting of an out-of-plane magnetized free layer and an in-plane polarizer is necessary to stabilize out-of-plane magnetization precession without the need of external magnetic fields. As the in-plane anisotropy is increased, a gradual tilting of the magnetization towards the in-plane easy direction is introduced, favouring zero-field dynamics over static in-plane states. Above a critical value, zero-field dynamics are no longer observed. The optimum ratio of in-plane shape to out-of-plane uniaxial anisotropy, for which large angle out-of-plane zero-field dynamics occur within the widest current range, is reported.

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Ewa Kowalska, Attila Kákay, Ciarán Fowley, Volker Sluka, Jürgen Lindner, Jürgen Fassbender, Alina M. Deac. 2018-10-05. Zero-field dynamics stabilized by in-plane shape anisotropy in MgO-based spin-torque oscillators. https://doi.org/10.1063/1.5081036

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