Analysis of an all-in-plane spin-torque oscillator using injection locking to an external microwave magnetic field

We experimentally study the magnetization dynamics of an all-in-plane spin-torque oscillator (AIP-STO) by using injection locking to an external microwave magnetic field. The AIP-STO exhibits multiple frequency signals corresponding not only to the oscillation frequencies of the magnetic layers but also to the difference between these frequencies. The oscillation frequency is identified based on the principle that injection locking occurs only to the signal corresponding to the magnetization oscillation. We also analyze the magnetization dynamics during injection locking by micromagnetic simulations. The results demonstrate that injection locking is a powerful tool for elucidating the oscillation of the AIP-STO.

[1]  H. Iwasaki,et al.  Design Concept of MAS Effect Dominant MAMR Head and Numerical Study , 2020, IEEE Transactions on Magnetics.

[2]  H. Sepehri-Amin,et al.  Design of spin-injection-layer in all-in-plane spin-torque-oscillator for microwave assisted magnetic recording , 2019, Journal of Magnetism and Magnetic Materials.

[3]  T. Taniguchi.  Synchronized, periodic, and chaotic dynamics in spin torque oscillator with two free layers , 2019, Journal of Magnetism and Magnetic Materials.

[4]  H. Kubota,et al.  Inducing out-of-plane precession of magnetization for microwave-assisted magnetic recording with an oscillating polarizer in a spin-torque oscillator , 2019, Applied Physics Letters.

[5]  M. Hayashi,et al.  High frequency out-of-plane oscillation with large cone angle in mag-flip spin torque oscillators for microwave assisted magnetic recording , 2017 .

[6]  M. Matsubara,et al.  Advantage of MAMR Read-Write Performance , 2016, IEEE Transactions on Magnetics.

[7]  Satoshi Okamoto,et al.  Microwave assisted magnetic recording technologies and related physics , 2015 .

[8]  K. Koi,et al.  Analysis of Effective Field Gradient in Microwave-Assisted Magnetic Recording , 2014, IEEE Transactions on Magnetics.

[9]  Christoph Vogler,et al.  A three-dimensional spin-diffusion model for micromagnetics , 2014, Scientific Reports.

[10]  K. Mizushima,et al.  Magnetization dynamics of a MgO-based spin-torque oscillator with a perpendicular polarizer layer and a planar free layer , 2012 .

[11]  Sergei Urazhdin,et al.  Fractional synchronization of spin-torque nano-oscillators. , 2010, Physical review letters.

[12]  Jian-Gang Zhu,et al.  Microwave Assisted Magnetic Recording Utilizing Perpendicular Spin Torque Oscillator With Switchable Perpendicular Electrodes , 2010, IEEE Transactions on Magnetics.

[13]  C. Kittel.  On the Theory of Ferromagnetic Resonance Absorption , 1948 .

[14]  J. Zhu,et al.  Microwave Assisted Magnetic Recording , 2008, IEEE Transactions on Magnetics.