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Zeitschriftenartikel:

E. Auerbach, D. Berkov, B. Pichler, N. Leder, S. Gider, H. Arthaber:
"Injection locking at fractional frequencies of magnetic tunnel junction (MTJ)-based read sensors'ferromagnetic resonance modes";
arXiv.org Cornell University Library, 1905.08183 (2019), S. 1 - 29.



Kurzfassung englisch:
Being nonlinear dynamic systems, magnetic read sensors should respond to an excitation signal of
a frequency considerably di erent from their natural ferromagnetic resonance (FMR) frequencies.Because of the magnetization dynamics' inherent nonlinear nature, the sensors' response should bemeasured at the DC, excitation frequency, and its multiples (harmonics). In this paper, we presentresults of such measurements, accomplished using a one-port nonlinear vector network analyzer(NVNA), which show distinct resonances at fractional frequencies of the free layer (FL) FMR mode.Identi cation of these resonances, resulting from the nonlinear nature of the spin-torque (ST)-induced magnetization dynamics, was performed using micromagnetic modeling. In particular,we show that the measured DC response at the above-mentioned fractional frequencies can beexplained by a low-order nonlinearity and strong magnetodipolar feedback between magnetic layersadjacent to an MgO barrier. Additionally, we determined that the simulated harmonic responseis strongly enhanced by the mutual ST e ect between these layers. Finally, we demonstrate thatthe read sensors' nonlinear magnetization dynamics and, by extension, their harmonic responseare highly sensitive to various magnetic and ST parameters. Thus, this study shows that usingNVNA measurements in conjunction with micromagnetic modeling can clarify the uncertainty in the definition of these parameters.

Erstellt aus der Publikationsdatenbank der Technischen Universität Wien.