Nanoscale physics

Different regimes of spin-torque microwave detector operation
Artemchuk P.Yu.1, Prokopenko O.V.1
1 Faculty of Radio Physics, Electronics and Computer Systems, Taras Shevchenko National University of Kyiv. Volodymyrska str., 64/13, Kyiv-01601, Ukraine.
E-mail: doompeter@ukr.net

Spin-torque microwave detector (STMD) based on a magnetic tunnel junction and employing the spin-torque diode effect [1] and the tunneling magnetoresistance effect is now considered as promising nanoscale detector of electromagnetic microwave signals having the volt-watt sensitivity that exceeds that of Schottky diodes [2]. In the typical quadratic regime of STMD operation an external microwave signal excites a small-amplitude magnetization precession in the detector’s free magnetic layer, which results in the quadratic dependence of the STMD output dc voltage on the amplitude of microwave signal [2].
In this work we introduce the classification of STMD operation regimes based on the characteristic dependence of output dc voltage of an STMD on the input microwave power. We analyze features of magnetization dynamics for an STMD operating in quasi-quadratic, quadratic, transient and linear regimes and obtain the conditions needed for the observation of each mentioned regimes. We also found conditions for the observation of quasi-chaotic magnetization dynamics in an STMD.
The publication contains the results of studies conducted by President’s of Ukraine grant for competitive projects (F 78) and is also based on the research provided by the grants F 76/34-2018 and F 83 of the State Fund for Fundamental Research of Ukraine. This work was also supported in part by the grants 16BF052-01 and 18BF052-01M from Taras Shevchenko National University of Kyiv and grant 7F from the National Academy of Sciences of Ukraine.

1.	Tulapurkar A.A., Suzuki Y., Fukushima A., Kubota H., Maehara H., Tsunekawa K., Djayaprawira D.D., Watanabe N. & Yuasa S. Spin-torque diode effect in magnetic tunnel junctions // Nature.-2005.-438.-P. 339-342.
2.	Prokopenko O.V., Krivorotov I.N., Meitzler T.J., Bankowski E., Tiberkevich V.S., Slavin A.N. Spin-Torque Microwave Detectors // In book: Magnonics: From Fundamentals to Applications. Topics in Applied Physics (Vol. 125) / Eds. S.O. Demokritov and A.N. Slavin. -Berlin: Springer-Verlag, 2013. -P. 143-161.