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MA: Fachverband Magnetismus
MA 16: INNOMAG e. V. Dissertation Prize
MA 16.3: Vortrag
Montag, 16. März 2020, 15:50–16:15, POT 6
Highly efficient domain wall motion in ferrimagnetic bi-layer systems at the angular momentum compensation temperature — •Robin Bläsing and Stuart S. P. Parkin — Max Planck Institute of Microstructure Physics
Highly efficient current-induced motion of chiral domain walls was recently demonstrated in synthetic antiferromagnetic (SAF) structures due to an exchange coupling torque (ECT). The ECT derives from the antiferromagnetic exchange coupling through a ruthenium spacer layer between the two perpendicularly magnetized layers that comprise the SAF. In my dissertation I report that the same ECT mechanism applies to ferrimagnetic bi-layers formed from adjacent Co and Gd layers. In particular, I show that the ECT is maximized at the temperature TA where the Co and Gd angular momenta balance each other, rather than at their magnetization compensation temperature TM. Since the device temperature is significantly increased by the current pulses, taking into account Joule heating is of major importance when determining TA. The velocity of the domain walls driven by electrical current is highly sensitive to longitudinal magnetic fields but I show that this is not the case near TA. My studies provide new insight into the ECT mechanism for ferrimagnetic systems. Additionally, the minimum threshold current density to move domain walls is significantly decreased in Co/Gd bi-layers compared to SAF structures. The high efficiency resulting from the ECT and low threshold current density makes my study important for advanced domain wall-based spintronic devices.