Analysis method of a spin-torque oscillator using dc resistance change during injection locking to an external microwave magnetic field

Nagarjuna Asam, Hirofumi Suto, Shingo Tamaru, Hossein Sepehri-Amin, Anton Bolyachkin, Tomoya Nakatani, Weinan Zhou, Hitoshi Kubota, Yuya Sakuraba

Research output: Contribution to journalArticlepeer-review

Abstract

Spin torque oscillators (STOs) that generate a persistent magnetization oscillation by spin-transfer torque are promising spintronic devices for various applications. In this study, we propose and experimentally demonstrate a method to characterize the magnetization dynamics of STOs using injection locking. By placing the STO near an antenna that generates a microwave magnetic field of a variable frequency, injection locking of the STO to the microwave field occurs when is in the locking range around the intrinsic oscillation frequency. During injection locking, the dc resistance of the STO exhibits a peak-and-valley dependence on W which originates from the modification of the magnetization trajectory induced by injection locking. Based on this principle, the oscillation frequency can be estimated by measuring the dc resistance change. Because this method does not require measuring the high-frequency magnetoresistance signal from the STO, which is used in the conventional method, it is advantageous in cases where the high-frequency magnetoresistance signal is undetectable or exhibits additional frequency components different from the oscillation frequency.

Original languageEnglish
Article number142405
JournalApplied Physics Letters
Volume119
Issue number14
DOIs
Publication statusPublished - 2021 Oct 4
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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