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Zeitschriftenartikel:

E. Auerbach, D. Berkov, B. Pichler, N. Leder, H. Arthaber, S. Gider:
"Injection Locking at Fractional Frequencies of Magnetic-Tunnel-Junction-BasedRead Sensors´ Ferromagnetic Resonance Modes";
Physical Review Applied, Vol. 12 (2019), No. 054022; S. 1 - 14.



Kurzfassung englisch:
Being nonlinear dynamic systems, magnetic read sensors should respond to an excitation signal of afrequency considerably different from their natural ferromagnetic resonance (FMR) frequencies. Becauseof the magnetization dynamics´ inherent nonlinear nature, the sensors´ response should be measuredat the dc, excitation frequency, and its multiples (harmonics). In this paper, we present results of suchmeasurements, accomplished using a one-port nonlinear vector network analyzer (NVNA), which showdistinct resonances at fractional frequencies of the free layer (FL) FMR mode. Identification of theseresonances, resulting from the nonlinear nature of the spin-torque-(ST-)induced magnetization dynam-ics, is performed using micromagnetic modeling. In particular, we show that the measured dc responseat the above-mentioned fractional frequencies can be explained by a low-order nonlinearity and strongmagnetodipolar feedback between magnetic layers adjacent to a MgO barrier. Additionally, we determinethat the simulated harmonic response is strongly enhanced by the mutual ST effect between these layers.Finally, we demonstrate that the read sensors´ nonlinear magnetization dynamics and, by extension, theirharmonic response are highly sensitive to various magnetic and ST parameters. Thus, this study showsthat using NVNA measurements in conjunction with micromagnetic modeling can clarify the uncertainty in the definition of these parameters.


"Offizielle" elektronische Version der Publikation (entsprechend ihrem Digital Object Identifier - DOI)
http://dx.doi.org/10.1103/PhysRevApplied.12.054022


Erstellt aus der Publikationsdatenbank der Technischen Universität Wien.