Magnetodynamics in orthogonal nanocontact spin-torque nano-oscillators based on magnetic tunnel junctions

Abstract

We demonstrate field and current controlled magnetodynamics in nanocontact spin-torque nano-oscillators (STNOs) based on orthogonal magnetic tunnel junctions (MTJs). We systematically analyze the microwave properties (frequency $f$, linewidth $\Delta f$, power $P$, and frequency tunability $df/dI$) with their physical origins---perpendicular magnetic anisotropy (PMA), damping-like and field-like spin transfer torque (STT), and voltage-controlled magnetic anisotropy (VCMA). These devices present several advantageous characteristics: high emission frequencies ($f>20$ GHz), high frequency tunability ($df/dI=0.25$~GHz/mA), and zero-field operation ($f\sim 4$ GHz). Furthermore, a detailed investigation of $f(H,I)$ reveals that $df/dI$ is mostly governed by the large VCMA (287~fJ/(V$\cdot$m)), while STT plays a negligible role.

arXiv comment13 pages, 4 figures

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Cited by in corpus (3)

• Magnetic Droplet Solitons
• Field-free high-frequency exchange-spring spin-torque nano-oscillators
• High Frequency Microwave Emission of a Tri-layer Magnetic Tunnel Junction in the Absence of External Bias-Magnetic Field