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 Δf, 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∼4 GHz). Furthermore, a detailed investigation of f(H,I) reveals that df/dI is mostly governed by the large VCMA (287~fJ/(V⋅m)), while STT plays a negligible role.
@article{arxiv.1907.10427,
title = {Magnetodynamics in orthogonal nanocontact spin-torque nano-oscillators based on magnetic tunnel junctions},
author = {S. Jiang and M. Ahlberg and S. Chung and A. Houshang and R. Ferreira and P. P. Freitas and J. Åkerman},
journal= {arXiv preprint arXiv:1907.10427},
year = {2019}
}